diff --git a/src/hooks/dhcp/lease_cmds/lease_cmds.cc b/src/hooks/dhcp/lease_cmds/lease_cmds.cc
index ee7f7c66e3..14d1f3ab4a 100644
--- a/src/hooks/dhcp/lease_cmds/lease_cmds.cc
+++ b/src/hooks/dhcp/lease_cmds/lease_cmds.cc
@@ -107,8 +107,8 @@ public:
 
         /// @brief Default constructor.
         Parameters()
-            :addr("::"), query_type(TYPE_ADDR), lease_type(Lease::TYPE_NA),
-             iaid(0) {
+            : addr("::"), query_type(TYPE_ADDR), lease_type(Lease::TYPE_NA),
+              iaid(0) {
         }
     };
 
@@ -303,11 +303,12 @@ public:
     ///
     /// @param parameters parameters extracted from the command.
     ///
-    /// @return Address of the lease to be deleted.
+    /// @return Lease of the lease to be deleted.
+    ///
     /// @throw InvalidParameter if the DUID is not found when needed to
     /// find the lease or if the query type is by HW address.
     /// @throw InvalidOperation if the query type is unknown.
-    IOAddress getIPv6AddressForDelete(const Parameters& parameters) const;
+    Lease6Ptr getIPv6LeaseForDelete(const Parameters& parameters) const;
 
     /// @brief Returns a map holding brief information about a lease which
     /// failed to be deleted, updated or added.
@@ -1018,19 +1019,21 @@ int
 LeaseCmdsImpl::lease4DelHandler(CalloutHandle& handle) {
     Parameters p;
     Lease4Ptr lease4;
-    IOAddress addr(IOAddress::IPV4_ZERO_ADDRESS());
     try {
         extractCommand(handle);
         p = getParameters(false, cmd_args_);
 
         switch (p.query_type) {
         case Parameters::TYPE_ADDR: {
-
             // If address was specified explicitly, let's use it as is.
-            addr = p.addr;
+            lease4 = LeaseMgrFactory::instance().getLease4(p.addr);
+            if (!lease4) {
+                setErrorResponse(handle, "IPv4 lease not found.", CONTROL_RESULT_EMPTY);
+                return (0);
+            }
             break;
         }
-        case Parameters::TYPE_HWADDR:
+        case Parameters::TYPE_HWADDR: {
             if (!p.hwaddr) {
                 isc_throw(InvalidParameter, "Program error: Query by hw-address "
                                             "requires hwaddr to be specified");
@@ -1042,12 +1045,9 @@ LeaseCmdsImpl::lease4DelHandler(CalloutHandle& handle) {
                 setErrorResponse(handle, "IPv4 lease not found.", CONTROL_RESULT_EMPTY);
                 return (0);
             }
-
-            // Found it, can use it as is.
-            addr = lease4->addr_;
             break;
-
-        case Parameters::TYPE_CLIENT_ID:
+        }
+        case Parameters::TYPE_CLIENT_ID: {
             if (!p.client_id) {
                 isc_throw(InvalidParameter, "Program error: Query by client-id "
                                             "requires client-id to be specified");
@@ -1059,25 +1059,19 @@ LeaseCmdsImpl::lease4DelHandler(CalloutHandle& handle) {
                 setErrorResponse(handle, "IPv4 lease not found.", CONTROL_RESULT_EMPTY);
                 return (0);
             }
-
-            // Found it, can use it as is.
-            addr = lease4->addr_;
             break;
-
-        case Parameters::TYPE_DUID:
+        }
+        case Parameters::TYPE_DUID: {
             isc_throw(InvalidParameter, "Delete by duid is not allowed in v4.");
             break;
-
+        }
         default: {
             isc_throw(InvalidOperation, "Unknown query type: " << static_cast<int>(p.query_type));
             break;
         }
         }
 
-        Lease4Ptr lease(new Lease4());
-        lease->addr_ = addr;
-
-        if (LeaseMgrFactory::instance().deleteLease(lease)) {
+        if (LeaseMgrFactory::instance().deleteLease(lease4)) {
             setSuccessResponse(handle, "IPv4 lease deleted.");
         } else {
             setErrorResponse (handle, "IPv4 lease not found.", CONTROL_RESULT_EMPTY);
@@ -1122,7 +1116,7 @@ LeaseCmdsImpl::lease6BulkApplyHandler(CalloutHandle& handle) {
         // Parse deleted leases without deleting them from the database
         // yet. If any of the deleted leases or new leases appears to be
         // malformed we can easily rollback.
-        std::list<std::pair<Parameters, IOAddress> > parsed_deleted_list;
+        std::list<std::pair<Parameters, Lease6Ptr> > parsed_deleted_list;
         if (deleted_leases) {
             auto leases_list = deleted_leases->listValue();
 
@@ -1130,9 +1124,9 @@ LeaseCmdsImpl::lease6BulkApplyHandler(CalloutHandle& handle) {
             for (auto lease_params : leases_list) {
                 // Parsing the lease may throw and it means that the lease
                 // information is malformed.
-                Parameters  p = getParameters(true, lease_params);
-                auto lease_addr = getIPv6AddressForDelete(p);
-                parsed_deleted_list.push_back(std::make_pair(p, lease_addr));
+                Parameters p = getParameters(true, lease_params);
+                auto lease = getIPv6AddressForDelete(p);
+                parsed_deleted_list.push_back(std::make_pair(p, lease));
             }
         }
 
@@ -1167,17 +1161,14 @@ LeaseCmdsImpl::lease6BulkApplyHandler(CalloutHandle& handle) {
 
                 // This part is outside of the try-catch because an exception
                 // indicates that the command is malformed.
-                Parameters  p = lease_params_pair.first;
-                auto lease_addr = lease_params_pair.second;
+                Parameters p = lease_params_pair.first;
+                auto lease = lease_params_pair.second;
 
                 try {
-                    if (!lease_addr.isV6Zero()) {
+                    if (lease) {
                         // This may throw if the lease couldn't be deleted for
                         // any reason, but we still want to proceed with other
                         // leases.
-                        Lease6Ptr lease(new Lease6());
-                        lease->addr_ = lease_addr;
-
                         if (LeaseMgrFactory::instance().deleteLease(lease)) {
                             ++success_count;
 
@@ -1292,16 +1283,21 @@ LeaseCmdsImpl::lease6DelHandler(CalloutHandle& handle) {
 
         switch (p.query_type) {
         case Parameters::TYPE_ADDR: {
-
             // If address was specified explicitly, let's use it as is.
-            addr = p.addr;
+
+            // Let's see if there's such a lease at all.
+            lease6 = LeaseMgrFactory::instance().getLease6(p.lease_type, p.addr);
+            if (!lease6) {
+                setErrorResponse(handle, "IPv6 lease not found.", CONTROL_RESULT_EMPTY);
+                return (0);
+            }
             break;
         }
-        case Parameters::TYPE_HWADDR:
+        case Parameters::TYPE_HWADDR: {
             isc_throw(InvalidParameter, "Delete by hw-address is not allowed in v6.");
             break;
-
-        case Parameters::TYPE_DUID:
+        }
+        case Parameters::TYPE_DUID: {
             if (!p.duid) {
                 isc_throw(InvalidParameter, "Program error: Query by duid "
                                             "requires duid to be specified");
@@ -1314,21 +1310,15 @@ LeaseCmdsImpl::lease6DelHandler(CalloutHandle& handle) {
                 setErrorResponse(handle, "IPv6 lease not found.", CONTROL_RESULT_EMPTY);
                 return (0);
             }
-
-            // Found it, can use it as is.
-            addr = lease6->addr_;
             break;
-
+        }
         default: {
             isc_throw(InvalidOperation, "Unknown query type: " << static_cast<int>(p.query_type));
             break;
         }
         }
 
-        Lease6Ptr lease(new Lease6());
-        lease->addr_ = addr;
-
-        if (LeaseMgrFactory::instance().deleteLease(lease)) {
+        if (LeaseMgrFactory::instance().deleteLease(lease6)) {
             setSuccessResponse(handle, "IPv6 lease deleted.");
         } else {
             setErrorResponse (handle, "IPv6 lease not found.", CONTROL_RESULT_EMPTY);
@@ -1509,23 +1499,28 @@ LeaseCmdsImpl::lease6WipeHandler(CalloutHandle& handle) {
     return (0);
 }
 
-IOAddress
-LeaseCmdsImpl::getIPv6AddressForDelete(const Parameters& parameters) const {
-    IOAddress addr = IOAddress::IPV6_ZERO_ADDRESS();
+Lease6Ptr
+LeaseCmdsImpl::getIPv6LeaseForDelete(const Parameters& parameters) const {
     Lease6Ptr lease6;
 
     switch (parameters.query_type) {
     case Parameters::TYPE_ADDR: {
-
         // If address was specified explicitly, let's use it as is.
-        addr = parameters.addr;
+
+        // Let's see if there's such a lease at all.
+        lease6 = LeaseMgrFactory::instance().getLease6(parameters.lease_type,
+                                                       parameters.addr);
+        if (!lease6) {
+            lease6.reset(new Lease6());
+            lease6->addr_ = parameters.addr;
+        }
         break;
     }
-    case Parameters::TYPE_HWADDR:
+    case Parameters::TYPE_HWADDR: {
         isc_throw(InvalidParameter, "Delete by hw-address is not allowed in v6.");
         break;
-
-    case Parameters::TYPE_DUID:
+    }
+    case Parameters::TYPE_DUID: {
         if (!parameters.duid) {
             isc_throw(InvalidParameter, "Program error: Query by duid "
                       "requires duid to be specified");
@@ -1536,18 +1531,14 @@ LeaseCmdsImpl::getIPv6AddressForDelete(const Parameters& parameters) const {
                                                        *parameters.duid,
                                                        parameters.iaid,
                                                        parameters.subnet_id);
-        if (lease6) {
-            addr = lease6->addr_;
-        }
-
-       break;
-
+        break;
+    }
     default:
         isc_throw(InvalidOperation, "Unknown query type: "
                   << static_cast<int>(parameters.query_type));
     }
 
-    return (addr);
+    return (lease6);
 }
 
 ElementPtr
diff --git a/src/lib/dhcpsrv/alloc_engine.cc b/src/lib/dhcpsrv/alloc_engine.cc
index 136676dd3a..fd9ab7f1be 100644
--- a/src/lib/dhcpsrv/alloc_engine.cc
+++ b/src/lib/dhcpsrv/alloc_engine.cc
@@ -30,6 +30,7 @@
 #include <hooks/hooks_manager.h>
 
 #include <boost/foreach.hpp>
+#include <boost/make_shared.hpp>
 
 #include <algorithm>
 #include <cstring>
@@ -3674,8 +3675,8 @@ AllocEngine::renewLease4(const Lease4Ptr& lease,
     // (the lease returned points directly to the lease4 object in the database)
     // We'll need it if we want to skip update (i.e. roll back renewal)
     /// @todo: remove this?
-    Lease4 old_values = *lease;
-    ctx.old_lease_.reset(new Lease4(old_values));
+    Lease4Ptr old_values = boost::make_shared<Lease4>(*lease);
+    ctx.old_lease_.reset(new Lease4(*old_values));
 
     // Update the lease with the information from the context.
     updateLease4Information(lease, ctx);
@@ -3686,7 +3687,6 @@ AllocEngine::renewLease4(const Lease4Ptr& lease,
         // involves execution of hooks and DNS update.
         if (ctx.old_lease_->expired()) {
             reclaimExpiredLease(ctx.old_lease_, ctx.callout_handle_);
-
         }
 
         lease->state_ = Lease::STATE_DEFAULT;
@@ -3756,7 +3756,7 @@ AllocEngine::renewLease4(const Lease4Ptr& lease,
     if (skip) {
         // Rollback changes (really useful only for memfile)
         /// @todo: remove this?
-        *lease = old_values;
+        *lease = *old_values;
     }
 
     return (lease);
diff --git a/src/lib/dhcpsrv/cql_lease_mgr.cc b/src/lib/dhcpsrv/cql_lease_mgr.cc
index 6ed7ce8ff1..2be3a07f5f 100644
--- a/src/lib/dhcpsrv/cql_lease_mgr.cc
+++ b/src/lib/dhcpsrv/cql_lease_mgr.cc
@@ -26,10 +26,11 @@
 #include <dhcp/hwaddr.h>
 
 #include <asiolink/io_address.h>
+#include <boost/make_shared.hpp>
 
 using namespace isc::data;
 using namespace isc::db;
-using isc::asiolink::IOAddress;
+using namespace isc::asiolink;
 
 namespace isc {
 namespace dhcp {
@@ -46,11 +47,12 @@ static constexpr char NULL_USER_CONTEXT[] = "";
 /// base to both of them, containing some common methods.
 class CqlLeaseExchange : public CqlExchange {
 public:
+
     /// @brief Constructor
     ///
     /// @param connection already open Cassandra connection.
     CqlLeaseExchange(const CqlConnection &connection)
-        : connection_(connection), valid_lifetime_(0), expire_(0),
+        : connection_(connection), valid_lifetime_(0), expire_(0), old_expire_(0),
           subnet_id_(0), fqdn_fwd_(cass_false), fqdn_rev_(cass_false),
           state_(0), user_context_(NULL_USER_CONTEXT) {
     }
@@ -75,6 +77,7 @@ public:
     virtual boost::any retrieve() override = 0;
 
 protected:
+
     /// @brief Database connection
     const CqlConnection &connection_;
 
@@ -87,6 +90,9 @@ protected:
     /// @brief Lease expiry time
     cass_int64_t expire_;
 
+    /// @brief Expiration time of lease before update
+    cass_int64_t old_expire_;
+
     /// @brief Subnet identifier
     cass_int32_t subnet_id_;
 
@@ -120,6 +126,7 @@ protected:
 /// in all CqlLeaseMgr::xxx4() calls where it is used.
 class CqlLease4Exchange : public CqlLeaseExchange {
 public:
+
     /// @brief Constructor
     ///
     /// The initialization of the variables here is only to satisfy
@@ -236,6 +243,7 @@ public:
     /// @}
 
 private:
+
     // Pointer to lease object
     Lease4Ptr lease_;
     // IPv4 address
@@ -270,7 +278,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       ") VALUES ( "
       "?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ? "
       ") "
-      "IF NOT EXISTS "}},
+      "IF NOT EXISTS "
+     }},
 
     // Updates existing IPv4 lease
     {UPDATE_LEASE4,
@@ -287,14 +296,16 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "state = ?, "
       "user_context = ? "
       "WHERE address = ? "
-      "IF EXISTS "}},
+      "IF expire = ? "
+     }},
 
     // Deletes existing IPv4 lease
     {DELETE_LEASE4,
      {DELETE_LEASE4,
       "DELETE FROM lease4 "
       "WHERE address = ? "
-      "IF EXISTS "}},
+      "IF expire = ? "
+     }},
 
     // Gets up to a certain number of expired IPv4 leases
     {GET_LEASE4_EXPIRE,
@@ -307,7 +318,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "AND valid_lifetime < 4294967295 "
       "AND expire < ? "
       "LIMIT ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
      // Gets an IPv4 lease(s)
      {GET_LEASE4,
@@ -315,7 +327,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
        "SELECT "
        "address, hwaddr, client_id, valid_lifetime, expire, subnet_id, "
        "fqdn_fwd, fqdn_rev, hostname, state, user_context "
-       "FROM lease4 "}},
+       "FROM lease4 "
+     }},
 
     // Gets an IPv4 lease with specified IPv4 address
     {GET_LEASE4_ADDR,
@@ -324,7 +337,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "address, hwaddr, client_id, valid_lifetime, expire, subnet_id, "
       "fqdn_fwd, fqdn_rev, hostname, state, user_context "
       "FROM lease4 "
-      "WHERE address = ? "}},
+      "WHERE address = ? "
+     }},
 
     // Gets an IPv4 lease(s) with specified client-id
     {GET_LEASE4_CLIENTID,
@@ -334,7 +348,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "fqdn_fwd, fqdn_rev, hostname, state, user_context "
       "FROM lease4 "
       "WHERE client_id = ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Gets an IPv4 lease with specified client-id and subnet-id
     {GET_LEASE4_CLIENTID_SUBID,
@@ -345,7 +360,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "FROM lease4 "
       "WHERE client_id = ? "
       "AND subnet_id = ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Gets all IPv4 leases with specified hardware address
     {GET_LEASE4_HWADDR,
@@ -355,7 +371,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "fqdn_fwd, fqdn_rev, hostname, state, user_context "
       "FROM lease4 "
       "WHERE hwaddr = ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Gets an IPv4 lease with specified hardware addr and subnet-id
     {GET_LEASE4_HWADDR_SUBID,
@@ -366,7 +383,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "FROM lease4 "
       "WHERE hwaddr = ? "
       "AND subnet_id = ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Get range of lease4 from first lease with a limit (paging)
     {GET_LEASE4_LIMIT,
@@ -376,7 +394,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "fqdn_fwd, fqdn_rev, hostname, state, user_context "
       "FROM lease4 "
       "LIMIT ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Get range of lease4 from address with a limit (paging)
     {GET_LEASE4_PAGE,
@@ -387,7 +406,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
       "FROM lease4 "
       "WHERE TOKEN(address) > TOKEN(?) "
       "LIMIT ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
      // Gets an IPv4 lease(s) with specified subnet-id
      {GET_LEASE4_SUBID,
@@ -407,7 +427,8 @@ StatementMap CqlLease4Exchange::tagged_statements_{
        "fqdn_fwd, fqdn_rev, hostname, state, user_context "
        "FROM lease4 "
        "WHERE hostname = ? "
-       "ALLOW FILTERING "}}
+       "ALLOW FILTERING "
+     }}
 };
 
 CqlLease4Exchange::CqlLease4Exchange(const CqlConnection &connection)
@@ -462,8 +483,7 @@ CqlLease4Exchange::createBindForInsert(const Lease4Ptr &lease, AnyArray &data) {
         // For convenience for external tools, this is converted to lease
         // expiry time (expire). The relationship is given by:
         // expire = cltt_ + valid_lft_
-        CqlExchange::convertToDatabaseTime(lease_->cltt_, lease_->valid_lft_,
-                                           expire_);
+        CqlExchange::convertToDatabaseTime(lease_->cltt_, lease_->valid_lft_, expire_);
 
         // subnet_id: int
         subnet_id_ = static_cast<cass_int32_t>(lease_->subnet_id_);
@@ -565,8 +585,7 @@ CqlLease4Exchange::createBindForUpdate(const Lease4Ptr &lease, AnyArray &data,
         // For convenience for external tools, this is converted to lease
         // expiry time (expire). The relationship is given by:
         // expire = cltt_ + valid_lft_
-        CqlExchange::convertToDatabaseTime(lease_->cltt_, lease_->valid_lft_,
-                                           expire_);
+        CqlExchange::convertToDatabaseTime(lease_->cltt_, lease_->valid_lft_, expire_);
 
         // subnet_id: int
         subnet_id_ = static_cast<cass_int32_t>(lease_->subnet_id_);
@@ -612,6 +631,8 @@ CqlLease4Exchange::createBindForUpdate(const Lease4Ptr &lease, AnyArray &data,
         data.add(&user_context_);
         data.add(&address_);
 
+        CqlExchange::convertToDatabaseTime(lease_->old_cltt_, lease_->old_valid_lft_, old_expire_);
+        data.add(&old_expire_);
     } catch (const Exception &ex) {
         isc_throw(DbOperationError,
                   "CqlLease4Exchange::createBindUpdate(): "
@@ -640,6 +661,8 @@ CqlLease4Exchange::createBindForDelete(const Lease4Ptr &lease, AnyArray &data,
         data.clear();
         data.add(&address_);
 
+        CqlExchange::convertToDatabaseTime(lease_->old_cltt_, lease_->old_valid_lft_, old_expire_);
+        data.add(&old_expire_);
     } catch (const Exception &ex) {
         isc_throw(DbOperationError,
                   "CqlLease4Exchange::createBindForDelete(): "
@@ -650,7 +673,6 @@ CqlLease4Exchange::createBindForDelete(const Lease4Ptr &lease, AnyArray &data,
 
 void
 CqlLease4Exchange::createBindForSelect(AnyArray &data, StatementTag /* unused */) {
-
     // Start with a fresh array.
     data.clear();
 
@@ -718,7 +740,7 @@ CqlLease4Exchange::retrieve() {
         time_t cltt = 0;
         CqlExchange::convertFromDatabaseTime(expire_, valid_lifetime_, cltt);
 
-        HWAddrPtr hwaddr(new HWAddr(hwaddr_, HTYPE_ETHER));
+        HWAddrPtr hwaddr = boost::make_shared<HWAddr>(hwaddr_, HTYPE_ETHER);
 
         uint32_t addr4 = static_cast<uint32_t>(address_);
 
@@ -731,10 +753,10 @@ CqlLease4Exchange::retrieve() {
             }
         }
 
-        Lease4Ptr result(new Lease4(addr4, hwaddr, client_id_.data(),
-                                    client_id_.size(), valid_lifetime_,
-                                    cltt, subnet_id_, fqdn_fwd_, fqdn_rev_,
-                                    hostname_));
+        Lease4Ptr result(boost::make_shared<Lease4>(addr4, hwaddr, client_id_.data(),
+                                                    client_id_.size(), valid_lifetime_,
+                                                    cltt, subnet_id_, fqdn_fwd_, fqdn_rev_,
+                                                    hostname_));
 
         result->state_ = state_;
 
@@ -809,8 +831,7 @@ CqlLease4Exchange::getExpiredLeases(const size_t &max_leases,
 
         // Retrieve leases from the database.
         Lease4Collection temp_collection;
-        getLeaseCollection(CqlLease4Exchange::GET_LEASE4_EXPIRE, data,
-                           temp_collection);
+        getLeaseCollection(CqlLease4Exchange::GET_LEASE4_EXPIRE, data, temp_collection);
 
         for (Lease4Ptr &lease : temp_collection) {
             expired_leases.push_back(lease);
@@ -832,6 +853,7 @@ CqlLease4Exchange::getExpiredLeases(const size_t &max_leases,
 /// in all CqlLeaseMgr::xxx6() calls where it is used.
 class CqlLease6Exchange : public CqlLeaseExchange {
 public:
+
     /// @brief Constructor
     ///
     /// The initialization of the variables here is only to satisfy
@@ -931,6 +953,7 @@ public:
     // @}
 
 private:
+
     /// @brief Lease
     Lease6Ptr lease_;
 
@@ -983,7 +1006,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       ") VALUES ("
       "?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?"
       ") "
-      "IF NOT EXISTS "}},
+      "IF NOT EXISTS "
+     }},
 
     // Updates existing IPv6 lease
     {UPDATE_LEASE6,
@@ -1006,14 +1030,16 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "state = ?, "
       "user_context = ? "
       "WHERE address = ? "
-      "IF EXISTS "}},
+      "IF expire = ? "
+     }},
 
     // Deletes existing IPv6 lease
     {DELETE_LEASE6,
      {DELETE_LEASE6,
       "DELETE FROM lease6 "
       "WHERE address = ? "
-      "IF EXISTS "}},
+      "IF expire = ? "
+     }},
 
     // Gets up to a certain number of expired IPv6 leases
     {GET_LEASE6_EXPIRE,
@@ -1027,7 +1053,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "AND valid_lifetime < 4294967295 "
       "AND expire < ? "
       "LIMIT ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Gets an IPv6 lease with specified IPv6 address
     {GET_LEASE6_ADDR,
@@ -1039,7 +1066,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "FROM lease6 "
       "WHERE address = ? "
       "AND lease_type = ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Gets an IPv6 lease with specified duid
     {GET_LEASE6_DUID,
@@ -1050,7 +1078,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "hwaddr_source, state, user_context "
       "FROM lease6 "
       "WHERE duid = ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Gets an IPv6 lease(s) with specified duid and iaid
     {GET_LEASE6_DUID_IAID,
@@ -1062,7 +1091,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "FROM lease6 "
       "WHERE duid = ? AND iaid = ? "
       "AND lease_type = ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Gets an IPv6 lease with specified duid, iaid and subnet-id
     {GET_LEASE6_DUID_IAID_SUBID,
@@ -1075,7 +1105,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "WHERE duid = ? AND iaid = ? "
       "AND lease_type = ? "
       "AND subnet_id = ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Get range of IPv6 leases from first lease with a limit (paging)
     {GET_LEASE6_LIMIT,
@@ -1086,7 +1117,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "hwaddr_source, state, user_context "
       "FROM lease6 "
       "LIMIT ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Get range of IPv6 leases from address with a limit (paging)
     {GET_LEASE6_PAGE,
@@ -1098,7 +1130,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "FROM lease6 "
       "WHERE TOKEN(address) > TOKEN(?) "
       "LIMIT ? "
-      "ALLOW FILTERING "}},
+      "ALLOW FILTERING "
+     }},
 
     // Gets an IPv6 lease(s) with specified hostname
     {GET_LEASE6_HOSTNAME,
@@ -1109,9 +1142,8 @@ StatementMap CqlLease6Exchange::tagged_statements_ = {
       "hwaddr_source, state, user_context "
       "FROM lease6 "
       "WHERE hostname = ? "
-      "ALLOW FILTERING "}},
-
-
+      "ALLOW FILTERING "
+     }}
 };
 
 CqlLease6Exchange::CqlLease6Exchange(const CqlConnection &connection)
@@ -1282,8 +1314,7 @@ CqlLease6Exchange::createBindForUpdate(const Lease6Ptr &lease, AnyArray &data,
         // For convenience for external tools, this is converted to lease
         // expiry time (expire). The relationship is given by:
         // expire = cltt_ + valid_lft_
-        CqlExchange::convertToDatabaseTime(lease_->cltt_, lease_->valid_lft_,
-                                           expire_);
+        CqlExchange::convertToDatabaseTime(lease_->cltt_, lease_->valid_lft_, expire_);
 
         // subnet_id: int
         subnet_id_ = static_cast<cass_int32_t>(lease_->subnet_id_);
@@ -1386,6 +1417,8 @@ CqlLease6Exchange::createBindForUpdate(const Lease6Ptr &lease, AnyArray &data,
         data.add(&user_context_);
         data.add(&address_);
 
+        CqlExchange::convertToDatabaseTime(lease_->old_cltt_, lease_->old_valid_lft_, old_expire_);
+        data.add(&old_expire_);
     } catch (const Exception &ex) {
         isc_throw(DbOperationError,
                   "CqlLease6Exchange::createBindForUpdate(): "
@@ -1420,6 +1453,8 @@ CqlLease6Exchange::createBindForDelete(const Lease6Ptr &lease, AnyArray &data,
         data.clear();
         data.add(&address_);
 
+        CqlExchange::convertToDatabaseTime(lease_->old_cltt_, lease_->old_valid_lft_, old_expire_);
+        data.add(&old_expire_);
     } catch (const Exception &ex) {
         isc_throw(DbOperationError,
                   "CqlLease6Exchange::createBindForDelete(): "
@@ -1430,7 +1465,6 @@ CqlLease6Exchange::createBindForDelete(const Lease6Ptr &lease, AnyArray &data,
 
 void
 CqlLease6Exchange::createBindForSelect(AnyArray &data, StatementTag /* unused */) {
-
     // Start with a fresh array.
     data.clear();
 
@@ -1527,11 +1561,11 @@ CqlLease6Exchange::retrieve() {
 
         IOAddress addr(address_);
 
-        DuidPtr duid(new DUID(duid_));
+        DuidPtr duid(boost::make_shared<DUID>(duid_));
 
         HWAddrPtr hwaddr;
         if (hwaddr_.size()) {
-            hwaddr.reset(new HWAddr(hwaddr_, hwtype_));
+            hwaddr = boost::make_shared<HWAddr>(hwaddr_, hwtype_);
             hwaddr->source_ = hwaddr_source_;
         }
 
@@ -1546,14 +1580,15 @@ CqlLease6Exchange::retrieve() {
 
         // Create the lease and set the cltt (after converting from the
         // expire time retrieved from the database).
-        Lease6Ptr result(new Lease6(static_cast<Lease::Type>(lease_type_), addr, duid,
-                                    iaid_, pref_lifetime_, valid_lifetime_,
-                                    subnet_id_, fqdn_fwd_, fqdn_rev_, hostname_,
-                                    hwaddr, prefix_len_));
+        Lease6Ptr result(boost::make_shared<Lease6>(static_cast<Lease::Type>(lease_type_), addr, duid,
+                                                    iaid_, pref_lifetime_, valid_lifetime_,
+                                                    subnet_id_, fqdn_fwd_, fqdn_rev_, hostname_,
+                                                    hwaddr, prefix_len_));
 
         time_t cltt = 0;
         CqlExchange::convertFromDatabaseTime(expire_, valid_lifetime_, cltt);
         result->cltt_ = cltt;
+        result->old_cltt_ = cltt;
 
         result->state_ = state_;
 
@@ -1629,8 +1664,7 @@ CqlLease6Exchange::getExpiredLeases(const size_t &max_leases,
 
         // Retrieve leases from the database.
         Lease6Collection temp_collection;
-        getLeaseCollection(CqlLease6Exchange::GET_LEASE6_EXPIRE, data,
-                           temp_collection);
+        getLeaseCollection(CqlLease6Exchange::GET_LEASE6_EXPIRE, data, temp_collection);
 
         for (Lease6Ptr &lease : temp_collection) {
             expired_leases.push_back(lease);
@@ -1645,6 +1679,7 @@ CqlLease6Exchange::getExpiredLeases(const size_t &max_leases,
 ///
 class CqlLeaseStatsQuery : public LeaseStatsQuery {
 public:
+
     /// @brief Constructor to query for all subnets' stats
     ///
     ///  The query created will return statistics for all subnets
@@ -1781,6 +1816,7 @@ public:
     static StatementMap tagged_statements_;
 
 private:
+
     /// @brief Database connection to use to execute the query
     CqlConnection& conn_;
 
@@ -2047,7 +2083,7 @@ CqlLeaseStatsQuery::executeSelect(const CqlConnection& connection, const AnyArra
 }
 
 CqlLeaseMgr::CqlLeaseMgr(const DatabaseConnection::ParameterMap &parameters)
-  : LeaseMgr(), parameters_(parameters), dbconn_(parameters) {
+    : parameters_(parameters), dbconn_(parameters) {
     // Validate the schema version first.
     std::pair<uint32_t, uint32_t> code_version(CQL_SCHEMA_VERSION_MAJOR,
                                                CQL_SCHEMA_VERSION_MINOR);
@@ -2098,6 +2134,10 @@ CqlLeaseMgr::addLease(const Lease4Ptr &lease) {
             .arg(exception.what());
         return false;
     }
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
+
     return true;
 }
 
@@ -2117,6 +2157,10 @@ CqlLeaseMgr::addLease(const Lease6Ptr &lease) {
             .arg(exception.what());
         return false;
     }
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
+
     return true;
 }
 
@@ -2563,6 +2607,9 @@ CqlLeaseMgr::updateLease4(const Lease4Ptr &lease) {
     } catch (const StatementNotApplied &exception) {
         isc_throw(NoSuchLease, exception.what());
     }
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
 }
 
 void
@@ -2579,6 +2626,9 @@ CqlLeaseMgr::updateLease6(const Lease6Ptr &lease) {
     } catch (const StatementNotApplied &exception) {
         isc_throw(NoSuchLease, exception.what());
     }
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
 }
 
 bool
diff --git a/src/lib/dhcpsrv/cql_lease_mgr.h b/src/lib/dhcpsrv/cql_lease_mgr.h
index cb20819500..b14991c0a3 100644
--- a/src/lib/dhcpsrv/cql_lease_mgr.h
+++ b/src/lib/dhcpsrv/cql_lease_mgr.h
@@ -41,6 +41,7 @@ namespace dhcp {
 /// and that the Kea schema has been created within it.
 class CqlLeaseMgr : public LeaseMgr {
 public:
+
     /// @brief Constructor
     ///
     /// Uses the following keywords in the parameters passed to it to
@@ -581,6 +582,7 @@ public:
     virtual void rollback() override;
 
 private:
+
     /// @brief Connection parameters
     db::DatabaseConnection::ParameterMap parameters_;
 
diff --git a/src/lib/dhcpsrv/lease.cc b/src/lib/dhcpsrv/lease.cc
index 3ac260af7b..a175b58d96 100644
--- a/src/lib/dhcpsrv/lease.cc
+++ b/src/lib/dhcpsrv/lease.cc
@@ -40,9 +40,10 @@ Lease::Lease(const isc::asiolink::IOAddress& addr,
              uint32_t valid_lft, SubnetID subnet_id, time_t cltt,
              const bool fqdn_fwd, const bool fqdn_rev,
              const std::string& hostname, const HWAddrPtr& hwaddr)
-    :addr_(addr), valid_lft_(valid_lft), cltt_(cltt), subnet_id_(subnet_id),
-     hostname_(boost::algorithm::to_lower_copy(hostname)), fqdn_fwd_(fqdn_fwd),
-     fqdn_rev_(fqdn_rev), hwaddr_(hwaddr), state_(STATE_DEFAULT) {
+    : addr_(addr), valid_lft_(valid_lft), old_valid_lft_(valid_lft),
+      cltt_(cltt), old_cltt_(cltt), subnet_id_(subnet_id),
+      hostname_(boost::algorithm::to_lower_copy(hostname)), fqdn_fwd_(fqdn_fwd),
+      fqdn_rev_(fqdn_rev), hwaddr_(hwaddr), state_(STATE_DEFAULT) {
 }
 
 
@@ -376,7 +377,9 @@ Lease4::operator=(const Lease4& other) {
     if (this != &other) {
         addr_ = other.addr_;
         valid_lft_ = other.valid_lft_;
+        old_valid_lft_ = other.old_valid_lft_;
         cltt_ = other.cltt_;
+        old_cltt_ = other.old_cltt_;
         subnet_id_ = other.subnet_id_;
         hostname_ = other.hostname_;
         fqdn_fwd_ = other.fqdn_fwd_;
@@ -477,6 +480,7 @@ Lease6::Lease6(Lease::Type type, const isc::asiolink::IOAddress& addr,
     }
 
     cltt_ = time(NULL);
+    old_cltt_ = cltt_;
 }
 
 Lease6::Lease6(Lease::Type type, const isc::asiolink::IOAddress& addr,
@@ -493,6 +497,7 @@ Lease6::Lease6(Lease::Type type, const isc::asiolink::IOAddress& addr,
     }
 
     cltt_ = time(NULL);
+    old_cltt_ = cltt_;
 }
 
 Lease6::Lease6()
@@ -581,7 +586,9 @@ Lease4::operator==(const Lease4& other) const {
             addr_ == other.addr_ &&
             subnet_id_ == other.subnet_id_ &&
             valid_lft_ == other.valid_lft_ &&
+            old_valid_lft_ == other.old_valid_lft_ &&
             cltt_ == other.cltt_ &&
+            old_cltt_ == other.old_cltt_ &&
             hostname_ == other.hostname_ &&
             fqdn_fwd_ == other.fqdn_fwd_ &&
             fqdn_rev_ == other.fqdn_rev_ &&
@@ -599,7 +606,9 @@ Lease6::operator==(const Lease6& other) const {
             iaid_ == other.iaid_ &&
             preferred_lft_ == other.preferred_lft_ &&
             valid_lft_ == other.valid_lft_ &&
+            old_valid_lft_ == other.old_valid_lft_ &&
             cltt_ == other.cltt_ &&
+            old_cltt_ == other.old_cltt_ &&
             subnet_id_ == other.subnet_id_ &&
             hostname_ == other.hostname_ &&
             fqdn_fwd_ == other.fqdn_fwd_ &&
diff --git a/src/lib/dhcpsrv/lease.h b/src/lib/dhcpsrv/lease.h
index 7354e2fa69..a1fdc94ebe 100644
--- a/src/lib/dhcpsrv/lease.h
+++ b/src/lib/dhcpsrv/lease.h
@@ -116,12 +116,23 @@ struct Lease : public isc::data::UserContext, public isc::data::CfgToElement {
     /// Expressed as number of seconds since cltt.
     uint32_t valid_lft_;
 
+    /// @brief Old valid lifetime
+    ///
+    /// Expressed as number of seconds since cltt before update.
+    uint32_t old_valid_lft_;
+
     /// @brief Client last transmission time
     ///
     /// Specifies a timestamp giving the time when the last transmission from a
     /// client was received.
     time_t cltt_;
 
+    /// @brief Old client last transmission time
+    ///
+    /// Specifies a timestamp giving the time when the last transmission from a
+    /// client was received before update.
+    time_t old_cltt_;
+
     /// @brief Subnet identifier
     ///
     /// Specifies the identification of the subnet to which the lease belongs.
diff --git a/src/lib/dhcpsrv/mysql_lease_mgr.cc b/src/lib/dhcpsrv/mysql_lease_mgr.cc
index ec399f75f9..2ec44e818c 100644
--- a/src/lib/dhcpsrv/mysql_lease_mgr.cc
+++ b/src/lib/dhcpsrv/mysql_lease_mgr.cc
@@ -15,6 +15,7 @@
 #include <util/multi_threading_mgr.h>
 
 #include <boost/array.hpp>
+#include <boost/make_shared.hpp>
 #include <boost/static_assert.hpp>
 #include <mysqld_error.h>
 
@@ -95,12 +96,12 @@ const size_t USER_CONTEXT_MAX_LEN = 8192;
 boost::array<TaggedStatement, MySqlLeaseMgr::NUM_STATEMENTS>
 tagged_statements = { {
     {MySqlLeaseMgr::DELETE_LEASE4,
-                    "DELETE FROM lease4 WHERE address = ?"},
+                    "DELETE FROM lease4 WHERE address = ? AND expire = ?"},
     {MySqlLeaseMgr::DELETE_LEASE4_STATE_EXPIRED,
                     "DELETE FROM lease4 "
                         "WHERE state = ? AND expire < ?"},
     {MySqlLeaseMgr::DELETE_LEASE6,
-                    "DELETE FROM lease6 WHERE address = ?"},
+                    "DELETE FROM lease6 WHERE address = ? AND expire = ?"},
     {MySqlLeaseMgr::DELETE_LEASE6_STATE_EXPIRED,
                     "DELETE FROM lease6 "
                         "WHERE state = ? AND expire < ?"},
@@ -286,7 +287,7 @@ tagged_statements = { {
                         "subnet_id = ?, fqdn_fwd = ?, fqdn_rev = ?, "
                         "hostname = ?, "
                         "state = ?, user_context = ? "
-                            "WHERE address = ?"},
+                            "WHERE address = ? AND expire = ?"},
     {MySqlLeaseMgr::UPDATE_LEASE6,
                     "UPDATE lease6 SET address = ?, duid = ?, "
                         "valid_lifetime = ?, expire = ?, subnet_id = ?, "
@@ -294,38 +295,33 @@ tagged_statements = { {
                         "prefix_len = ?, fqdn_fwd = ?, fqdn_rev = ?, "
                         "hostname = ?, hwaddr = ?, hwtype = ?, hwaddr_source = ?, "
                         "state = ?, user_context = ? "
-                            "WHERE address = ?"},
+                            "WHERE address = ? AND expire = ?"},
     {MySqlLeaseMgr::ALL_LEASE4_STATS,
-     "SELECT subnet_id, state, leases as state_count"
-     "  FROM lease4_stat ORDER BY subnet_id, state"},
-
+                    "SELECT subnet_id, state, leases as state_count "
+                        "FROM lease4_stat ORDER BY subnet_id, state"},
     {MySqlLeaseMgr::SUBNET_LEASE4_STATS,
-     "SELECT subnet_id, state, leases as state_count"
-     "  FROM lease4_stat "
-     "  WHERE subnet_id = ? "
-     "  ORDER BY state"},
-
+                    "SELECT subnet_id, state, leases as state_count "
+                        "FROM lease4_stat "
+                        "WHERE subnet_id = ? "
+                        "ORDER BY state"},
     {MySqlLeaseMgr::SUBNET_RANGE_LEASE4_STATS,
-     "SELECT subnet_id, state, leases as state_count"
-     "  FROM lease4_stat "
-     "  WHERE subnet_id >= ? and subnet_id <= ? "
-     "  ORDER BY subnet_id, state"},
-
+                    "SELECT subnet_id, state, leases as state_count "
+                        "FROM lease4_stat "
+                        "WHERE subnet_id >= ? and subnet_id <= ? "
+                        "ORDER BY subnet_id, state"},
     {MySqlLeaseMgr::ALL_LEASE6_STATS,
-     "SELECT subnet_id, lease_type, state, leases as state_count"
-     "  FROM lease6_stat ORDER BY subnet_id, lease_type, state" },
-
+                    "SELECT subnet_id, lease_type, state, leases as state_count "
+                        "FROM lease6_stat ORDER BY subnet_id, lease_type, state"},
     {MySqlLeaseMgr::SUBNET_LEASE6_STATS,
-     "SELECT subnet_id, lease_type, state, leases as state_count"
-     "  FROM lease6_stat "
-     "  WHERE subnet_id = ? "
-     "  ORDER BY lease_type, state" },
-
+                    "SELECT subnet_id, lease_type, state, leases as state_count "
+                        "FROM lease6_stat "
+                        "WHERE subnet_id = ? "
+                        "ORDER BY lease_type, state"},
     {MySqlLeaseMgr::SUBNET_RANGE_LEASE6_STATS,
-     "SELECT subnet_id, lease_type, state, leases as state_count"
-     "  FROM lease6_stat "
-     "  WHERE subnet_id >= ? and subnet_id <= ? "
-     "  ORDER BY subnet_id, lease_type, state" }
+                    "SELECT subnet_id, lease_type, state, leases as state_count "
+                        "FROM lease6_stat "
+                        "WHERE subnet_id >= ? and subnet_id <= ? "
+                        "ORDER BY subnet_id, lease_type, state"}
     }
 };
 
@@ -343,6 +339,7 @@ namespace dhcp {
 
 class MySqlLeaseExchange {
 public:
+
     /// @brief Set error indicators
     ///
     /// Sets the error indicator for each of the MYSQL_BIND elements.  It points
@@ -419,6 +416,7 @@ class MySqlLease4Exchange : public MySqlLeaseExchange {
     static const size_t LEASE_COLUMNS = 11;
 
 public:
+
     /// @brief Constructor
     ///
     /// The initialization of the variables here is only to satisfy cppcheck -
@@ -649,7 +647,6 @@ public:
     /// Creates a MYSQL_BIND array to receive Lease4 data from the database.
     /// After data is successfully received, getLeaseData() can be used to copy
     /// it to a Lease6 object.
-    ///
     std::vector<MYSQL_BIND> createBindForReceive() {
 
         // Initialize MYSQL_BIND array.
@@ -756,7 +753,7 @@ public:
 
         // Add the data to the vector.  Note the end element is one after the
         // end of the array.
-        return(std::vector<MYSQL_BIND>(&bind_[0], &bind_[LEASE_COLUMNS]));
+        return (std::vector<MYSQL_BIND>(&bind_[0], &bind_[LEASE_COLUMNS]));
     }
 
     /// @brief Copy Received Data into Lease4 Object
@@ -788,7 +785,7 @@ public:
         std::string hostname(hostname_buffer_,
                              hostname_buffer_ + hostname_length_);
 
-        /// Set hardware address if it was set
+        // Set hardware address if it was set
         HWAddrPtr hwaddr;
         if (hwaddr_null_ == MLM_FALSE) {
             hwaddr.reset(new HWAddr(hwaddr_buffer_, hwaddr_length_, HTYPE_ETHER));
@@ -811,9 +808,12 @@ public:
             }
         }
 
-        Lease4Ptr lease(new Lease4(addr4_, hwaddr, client_id_buffer_,
-                                   client_id_length_, valid_lifetime_, cltt,
-                                   subnet_id_, fqdn_fwd_, fqdn_rev_, hostname));
+        Lease4Ptr lease(boost::make_shared<Lease4>(addr4_, hwaddr,
+                                                   client_id_buffer_,
+                                                   client_id_length_,
+                                                   valid_lifetime_, cltt,
+                                                   subnet_id_, fqdn_fwd_,
+                                                   fqdn_rev_, hostname));
 
         // Set state.
         lease->state_ = state_;
@@ -844,30 +844,30 @@ private:
     // Note: All array lengths are equal to the corresponding variable in the
     //       schema.
     // Note: Arrays are declared fixed length for speed of creation
-    uint32_t               addr4_;                     ///< IPv4 address
-    MYSQL_BIND             bind_[LEASE_COLUMNS];       ///< Bind array
-    std::string            columns_[LEASE_COLUMNS];    ///< Column names
-    my_bool                error_[LEASE_COLUMNS];      ///< Error array
-    std::vector<uint8_t>   hwaddr_;                    ///< Hardware address
-    uint8_t                hwaddr_buffer_[HWAddr::MAX_HWADDR_LEN]; ///< Hardware address buffer
-    unsigned long          hwaddr_length_;             ///< Hardware address length
-    my_bool                hwaddr_null_;               ///< Used when HWAddr is null
-    std::vector<uint8_t>   client_id_;                 ///< Client identification
-    uint8_t                client_id_buffer_[ClientId::MAX_CLIENT_ID_LEN]; ///< Client ID buffer
-    unsigned long          client_id_length_;          ///< Client ID address length
-    my_bool                client_id_null_;            ///< Is Client ID null?
-    MYSQL_TIME             expire_;                    ///< Lease expiry time
-    Lease4Ptr              lease_;                     ///< Pointer to lease object
-    uint32_t               subnet_id_;                 ///< Subnet identification
-    uint32_t               valid_lifetime_;            ///< Lease time
-    my_bool                fqdn_fwd_;                  ///< Has forward DNS update been performed
-    my_bool                fqdn_rev_;                  ///< Has reverse DNS update been performed
-    char                   hostname_buffer_[HOSTNAME_MAX_LEN]; ///< Client hostname
-    unsigned long          hostname_length_;           ///< Client hostname length
-    uint32_t               state_;                     ///< Lease state
-    char                   user_context_[USER_CONTEXT_MAX_LEN]; ///< User context
-    unsigned long          user_context_length_;       ///< User context length
-    my_bool                user_context_null_;         ///< Is user context null?
+    uint32_t             addr4_;                                         ///< IPv4 address
+    MYSQL_BIND           bind_[LEASE_COLUMNS];                           ///< Bind array
+    std::string          columns_[LEASE_COLUMNS];                        ///< Column names
+    my_bool              error_[LEASE_COLUMNS];                          ///< Error array
+    Lease4Ptr            lease_;                                         ///< Pointer to lease object
+    std::vector<uint8_t> hwaddr_;                                        ///< Hardware address
+    uint8_t              hwaddr_buffer_[HWAddr::MAX_HWADDR_LEN];         ///< Hardware address buffer
+    unsigned long        hwaddr_length_;                                 ///< Length of Hardware address
+    my_bool              hwaddr_null_;                                   ///< Used when Hardware address is null
+    std::vector<uint8_t> client_id_;                                     ///< Client identification
+    uint8_t              client_id_buffer_[ClientId::MAX_CLIENT_ID_LEN]; ///< Client ID buffer
+    unsigned long        client_id_length_;                              ///< Client ID address length
+    my_bool              client_id_null_;                                ///< Used when Client ID is null
+    MYSQL_TIME           expire_;                                        ///< Lease expire time
+    uint32_t             subnet_id_;                                     ///< Subnet identification
+    uint32_t             valid_lifetime_;                                ///< Lease time
+    my_bool              fqdn_fwd_;                                      ///< Has forward DNS update been performed
+    my_bool              fqdn_rev_;                                      ///< Has reverse DNS update been performed
+    char                 hostname_buffer_[HOSTNAME_MAX_LEN];             ///< Client hostname
+    unsigned long        hostname_length_;                               ///< Length of client hostname
+    uint32_t             state_;                                         ///< Lease state
+    char                 user_context_[USER_CONTEXT_MAX_LEN];            ///< User context
+    unsigned long        user_context_length_;                           ///< Length of user context
+    my_bool              user_context_null_;                             ///< Used when user context is null
 };
 
 /// @brief Exchange MySQL and Lease6 Data
@@ -888,16 +888,17 @@ class MySqlLease6Exchange : public MySqlLeaseExchange {
     static const size_t LEASE_COLUMNS = 17;
 
 public:
+
     /// @brief Constructor
     ///
     /// The initialization of the variables here is only to satisfy cppcheck -
     /// all variables are initialized/set in the methods before they are used.
-    MySqlLease6Exchange() : addr6_length_(0), duid_length_(0),
-                            iaid_(0), lease_type_(0), prefixlen_(0),
+    MySqlLease6Exchange() : addr6_length_(0), hwaddr_length_(0),
+                            hwaddr_null_(MLM_FALSE), duid_length_(0),
+                            iaid_(0), lease_type_(0), prefix_len_(0),
                             pref_lifetime_(0), subnet_id_(0), valid_lifetime_(0),
                             fqdn_fwd_(false), fqdn_rev_(false),
-                            hostname_length_(0), hwaddr_length_(0),
-                            hwaddr_null_(MLM_FALSE), hwtype_(0), hwaddr_source_(0),
+                            hostname_length_(0), hwtype_(0), hwaddr_source_(0),
                             state_(0), user_context_length_(0),
                             user_context_null_(MLM_FALSE) {
         memset(addr6_buffer_, 0, sizeof(addr6_buffer_));
@@ -999,7 +1000,7 @@ public:
             // expire: timestamp
             // The lease structure holds the client last transmission time (cltt_)
             // For convenience for external tools, this is converted to lease
-            /// expiry time (expire).  The relationship is given by:
+            // expiry time (expire).  The relationship is given by:
             //
             // expire = cltt_ + valid_lft_
             // Avoid overflow
@@ -1108,7 +1109,7 @@ public:
                 bind_[12].is_null = &hwaddr_null_;
             }
 
-            // hwtype
+            // hardware source: unsigned int (32 bits)
             if (hwaddr) {
                 hwtype_ = lease->hwaddr_->htype_;
                 bind_[13].buffer_type = MYSQL_TYPE_SHORT;
@@ -1127,7 +1128,7 @@ public:
                 bind_[13].is_null = &hwaddr_null_;
             }
 
-            /// Hardware source
+            // hardware source: unsigned int (32 bits)
             if (hwaddr) {
                 hwaddr_source_ = lease->hwaddr_->source_;
                 bind_[14].buffer_type = MYSQL_TYPE_LONG;
@@ -1266,7 +1267,7 @@ public:
 
         // prefix_len: unsigned tinyint
         bind_[8].buffer_type = MYSQL_TYPE_TINY;
-        bind_[8].buffer = reinterpret_cast<char*>(&prefixlen_);
+        bind_[8].buffer = reinterpret_cast<char*>(&prefix_len_);
         bind_[8].is_unsigned = MLM_TRUE;
         // bind_[8].is_null = &MLM_FALSE; // commented out for performance
                                           // reasons, see memset() above
@@ -1337,7 +1338,7 @@ public:
 
         // Add the data to the vector.  Note the end element is one after the
         // end of the array.
-        return(std::vector<MYSQL_BIND>(&bind_[0], &bind_[LEASE_COLUMNS]));
+        return (std::vector<MYSQL_BIND>(&bind_[0], &bind_[LEASE_COLUMNS]));
     }
 
     /// @brief Copy Received Data into Lease6 Object
@@ -1389,7 +1390,7 @@ public:
         std::string hostname(hostname_buffer_,
                              hostname_buffer_ + hostname_length_);
 
-        /// Set hardware address if it was set
+        // Set hardware address if it was set
         HWAddrPtr hwaddr;
         if (hwaddr_null_ == MLM_FALSE) {
             hwaddr.reset(new HWAddr(hwaddr_buffer_, hwaddr_length_, hwtype_));
@@ -1415,10 +1416,12 @@ public:
 
         // Create the lease and set the cltt (after converting from the
         // expire time retrieved from the database).
-        Lease6Ptr result(new Lease6(type, addr, duid_ptr, iaid_,
-                                    pref_lifetime_, valid_lifetime_,
-                                    subnet_id_, fqdn_fwd_, fqdn_rev_,
-                                    hostname, hwaddr, prefixlen_));
+        Lease6Ptr result(boost::make_shared<Lease6>(type, addr, duid_ptr, iaid_,
+                                                    pref_lifetime_,
+                                                    valid_lifetime_, subnet_id_,
+                                                    fqdn_fwd_, fqdn_rev_,
+                                                    hostname, hwaddr,
+                                                    prefix_len_));
         time_t cltt = 0;
         // Recover from overflow
         uint32_t valid_lft = valid_lifetime_;
@@ -1427,6 +1430,7 @@ public:
         }
         MySqlConnection::convertFromDatabaseTime(expire_, valid_lft, cltt);
         result->cltt_ = cltt;
+        result->old_cltt_ = cltt;
 
         // Set state.
         result->state_ = state_;
@@ -1453,41 +1457,41 @@ public:
     }
 
 private:
+
     // Note: All array lengths are equal to the corresponding variable in the
     // schema.
     // Note: arrays are declared fixed length for speed of creation
-    std::string            addr6_;                     ///< String form of address
-    char                   addr6_buffer_[ADDRESS6_TEXT_MAX_LEN + 1]; ///< Character
-                                                       ///< array form of V6 address
-    unsigned long          addr6_length_;              ///< Length of the address
-    MYSQL_BIND             bind_[LEASE_COLUMNS];       ///< Bind array
-    std::string            columns_[LEASE_COLUMNS];    ///< Column names
-    std::vector<uint8_t>   duid_;                      ///< Client identification
-    uint8_t                duid_buffer_[DUID::MAX_DUID_LEN]; ///< Buffer form of DUID
-    unsigned long          duid_length_;               ///< Length of the DUID
-    my_bool                error_[LEASE_COLUMNS];      ///< Error indicators
-    MYSQL_TIME             expire_;                    ///< Lease expiry time
-    uint32_t               iaid_;                      ///< Identity association ID
-    Lease6Ptr              lease_;                     ///< Pointer to lease object
-    uint8_t                lease_type_;                ///< Lease type
-    uint8_t                prefixlen_;                 ///< Prefix length
-    uint32_t               pref_lifetime_;             ///< Preferred lifetime
-    uint32_t               subnet_id_;                 ///< Subnet identification
-    uint32_t               valid_lifetime_;            ///< Lease time
-    my_bool                fqdn_fwd_;                  ///< Has forward DNS update been performed
-    my_bool                fqdn_rev_;                  ///< Has reverse DNS update been performed
-    char                   hostname_buffer_[HOSTNAME_MAX_LEN]; ///< Client hostname
-    unsigned long          hostname_length_;           ///< Client hostname length
-    uint8_t                hwaddr_buffer_[HWAddr::MAX_HWADDR_LEN]; ///< Buffer form of Hardware address
-    std::vector<uint8_t>   hwaddr_;                    ///< Hardware address (optional)
-    unsigned long          hwaddr_length_;             ///< Aux. variable denoting hwaddr_ size()
-    my_bool                hwaddr_null_;               ///< Used when HWAddr is null
-    uint16_t               hwtype_;                    ///< Hardware type
-    uint32_t               hwaddr_source_;             ///< Source of the hardware address
-    uint32_t               state_;                     ///< Lease state.
-    char                   user_context_[USER_CONTEXT_MAX_LEN]; ///< User context
-    unsigned long          user_context_length_;       ///< User context length
-    my_bool                user_context_null_;         ///< Is user context null?
+    std::string          addr6_;                                   ///< Address
+    char                 addr6_buffer_[ADDRESS6_TEXT_MAX_LEN + 1]; ///< Address buffer
+    unsigned long        addr6_length_;                            ///< Length of address
+    MYSQL_BIND           bind_[LEASE_COLUMNS];                     ///< Bind array
+    std::string          columns_[LEASE_COLUMNS];                  ///< Column names
+    my_bool              error_[LEASE_COLUMNS];                    ///< Error array
+    Lease6Ptr            lease_;                                   ///< Pointer to lease object
+    std::vector<uint8_t> hwaddr_;                                  ///< Hardware address
+    uint8_t              hwaddr_buffer_[HWAddr::MAX_HWADDR_LEN];   ///< Hardware address buffer
+    unsigned long        hwaddr_length_;                           ///< Length of Hardware address
+    my_bool              hwaddr_null_;                             ///< Used when Hardware address is null
+    std::vector<uint8_t> duid_;                                    ///< DUID
+    uint8_t              duid_buffer_[DUID::MAX_DUID_LEN];         ///< DUID buffer
+    unsigned long        duid_length_;                             ///< Length of DUID
+    MYSQL_TIME           expire_;                                  ///< Lease expire time
+    uint32_t             iaid_;                                    ///< Identity association ID
+    uint8_t              lease_type_;                              ///< Lease type
+    uint8_t              prefix_len_;                              ///< Prefix length
+    uint32_t             pref_lifetime_;                           ///< Preferred lifetime
+    uint32_t             subnet_id_;                               ///< Subnet identification
+    uint32_t             valid_lifetime_;                          ///< Lease time
+    my_bool              fqdn_fwd_;                                ///< Has forward DNS update been performed
+    my_bool              fqdn_rev_;                                ///< Has reverse DNS update been performed
+    char                 hostname_buffer_[HOSTNAME_MAX_LEN];       ///< Client hostname
+    unsigned long        hostname_length_;                         ///< Length of client hostname
+    uint16_t             hwtype_;                                  ///< Hardware type
+    uint32_t             hwaddr_source_;                           ///< Source of the hardware address
+    uint32_t             state_;                                   ///< Lease state
+    char                 user_context_[USER_CONTEXT_MAX_LEN];      ///< User context
+    unsigned long        user_context_length_;                     ///< Length of user context
+    my_bool              user_context_null_;                       ///< Used when user context is null
 };
 
 /// @brief MySql derivation of the statistical lease data query
@@ -1499,6 +1503,7 @@ private:
 ///
 class MySqlLeaseStatsQuery : public LeaseStatsQuery {
 public:
+
     /// @brief Constructor to query for all subnets' stats
     ///
     ///  The query created will return statistics for all subnets
@@ -1669,6 +1674,7 @@ public:
     }
 
 private:
+
     /// @brief Validate the statement index passed to the constructor
     /// Safely fetch the statement from the connection based on statement index
     /// @throw  BadValue if statement index is out of range
@@ -1698,10 +1704,13 @@ private:
 
     /// @brief Receives subnet ID when fetching a row
     uint32_t subnet_id_;
+
     /// @brief Receives the lease type when fetching a row
     uint32_t lease_type_;
+
     /// @brief Receives the lease state when fetching a row
     uint32_t state_;
+
     /// @brief Receives the state count when fetching a row
     int64_t state_count_;
 };
@@ -1854,7 +1863,12 @@ MySqlLeaseMgr::addLease(const Lease4Ptr& lease) {
     std::vector<MYSQL_BIND> bind = ctx->exchange4_->createBindForSend(lease);
 
     // ... and drop to common code.
-    return (addLeaseCommon(ctx, INSERT_LEASE4, bind));
+    auto result = addLeaseCommon(ctx, INSERT_LEASE4, bind);
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
+
+    return (result);
 }
 
 bool
@@ -1871,7 +1885,12 @@ MySqlLeaseMgr::addLease(const Lease6Ptr& lease) {
     std::vector<MYSQL_BIND> bind = ctx->exchange6_->createBindForSend(lease);
 
     // ... and drop to common code.
-    return (addLeaseCommon(ctx, INSERT_LEASE6, bind));
+    auto result = addLeaseCommon(ctx, INSERT_LEASE6, bind);
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
+
+    return (result);
 }
 
 // Extraction of leases from the database.
@@ -1900,12 +1919,13 @@ MySqlLeaseMgr::addLease(const Lease6Ptr& lease) {
 // holding zero or one leases into an appropriate Lease object.
 
 template <typename Exchange, typename LeaseCollection>
-void MySqlLeaseMgr::getLeaseCollection(MySqlLeaseContextPtr ctx,
-                                       StatementIndex stindex,
-                                       MYSQL_BIND* bind,
-                                       Exchange& exchange,
-                                       LeaseCollection& result,
-                                       bool single) const {
+void
+MySqlLeaseMgr::getLeaseCollection(MySqlLeaseContextPtr ctx,
+                                  StatementIndex stindex,
+                                  MYSQL_BIND* bind,
+                                  Exchange& exchange,
+                                  LeaseCollection& result,
+                                  bool single) const {
 
     int status;
 
@@ -1964,9 +1984,10 @@ void MySqlLeaseMgr::getLeaseCollection(MySqlLeaseContextPtr ctx,
     }
 }
 
-void MySqlLeaseMgr::getLease(MySqlLeaseContextPtr ctx,
-                             StatementIndex stindex, MYSQL_BIND* bind,
-                             Lease4Ptr& result) const {
+void
+MySqlLeaseMgr::getLease(MySqlLeaseContextPtr ctx,
+                        StatementIndex stindex, MYSQL_BIND* bind,
+                        Lease4Ptr& result) const {
     // Create appropriate collection object and get all leases matching
     // the selection criteria.  The "single" parameter is true to indicate
     // that the called method should throw an exception if multiple
@@ -1983,9 +2004,10 @@ void MySqlLeaseMgr::getLease(MySqlLeaseContextPtr ctx,
     }
 }
 
-void MySqlLeaseMgr::getLease(MySqlLeaseContextPtr ctx,
-                             StatementIndex stindex, MYSQL_BIND* bind,
-                             Lease6Ptr& result) const {
+void
+MySqlLeaseMgr::getLease(MySqlLeaseContextPtr ctx,
+                        StatementIndex stindex, MYSQL_BIND* bind,
+                        Lease6Ptr& result) const {
     // Create appropriate collection object and get all leases matching
     // the selection criteria.  The "single" parameter is true to indicate
     // that the called method should throw an exception if multiple
@@ -2686,15 +2708,22 @@ MySqlLeaseMgr::updateLeaseCommon(MySqlLeaseContextPtr ctx,
     // See how many rows were affected.  The statement should only update a
     // single row.
     int affected_rows = mysql_stmt_affected_rows(ctx->conn_.statements_[stindex]);
+
+    // Check success case first as it is the most likely outcome.
+    if (affected_rows == 1) {
+        return;
+    }
+
+    // If no rows affected, lease doesn't exist.
     if (affected_rows == 0) {
         isc_throw(NoSuchLease, "unable to update lease for address " <<
-                  lease->addr_ << " as it does not exist");
-    } else if (affected_rows > 1) {
-        // Should not happen - primary key constraint should only have selected
-        // one row.
-        isc_throw(DbOperationError, "apparently updated more than one lease "
-                  "that had the address " << lease->addr_);
+                  lease->addr_.toText() << " as it does not exist");
     }
+
+    // Should not happen - primary key constraint should only have selected
+    // one row.
+    isc_throw(DbOperationError, "apparently updated more than one lease "
+              "that had the address " << lease->addr_.toText());
 }
 
 void
@@ -2712,17 +2741,30 @@ MySqlLeaseMgr::updateLease4(const Lease4Ptr& lease) {
     std::vector<MYSQL_BIND> bind = ctx->exchange4_->createBindForSend(lease);
 
     // Set up the WHERE clause and append it to the MYSQL_BIND array
-    MYSQL_BIND where;
-    memset(&where, 0, sizeof(where));
+    MYSQL_BIND inbind[2];
+    memset(inbind, 0, sizeof(inbind));
 
     uint32_t addr4 = lease->addr_.toUint32();
-    where.buffer_type = MYSQL_TYPE_LONG;
-    where.buffer = reinterpret_cast<char*>(&addr4);
-    where.is_unsigned = MLM_TRUE;
-    bind.push_back(where);
+    inbind[0].buffer_type = MYSQL_TYPE_LONG;
+    inbind[0].buffer = reinterpret_cast<char*>(&addr4);
+    inbind[0].is_unsigned = MLM_TRUE;
+
+    bind.push_back(inbind[0]);
+
+    MYSQL_TIME expire;
+    MySqlConnection::convertToDatabaseTime(lease->old_cltt_, lease->old_valid_lft_,
+                                           expire);
+    inbind[1].buffer_type = MYSQL_TYPE_TIMESTAMP;
+    inbind[1].buffer = reinterpret_cast<char*>(&expire);
+    inbind[1].buffer_length = sizeof(expire);
+
+    bind.push_back(inbind[1]);
 
     // Drop to common update code
     updateLeaseCommon(ctx, stindex, &bind[0], lease);
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
 }
 
 void
@@ -2740,23 +2782,36 @@ MySqlLeaseMgr::updateLease6(const Lease6Ptr& lease) {
     // Create the MYSQL_BIND array for the data being updated
     std::vector<MYSQL_BIND> bind = ctx->exchange6_->createBindForSend(lease);
 
-    // Set up the WHERE clause value
-    MYSQL_BIND where;
-    memset(&where, 0, sizeof(where));
+    // Set up the WHERE clause and append it to the MYSQL_BIND array
+    MYSQL_BIND inbind[2];
+    memset(inbind, 0, sizeof(inbind));
 
     std::string addr6 = lease->addr_.toText();
     unsigned long addr6_length = addr6.size();
 
     // See the earlier description of the use of "const_cast" when accessing
     // the address for an explanation of the reason.
-    where.buffer_type = MYSQL_TYPE_STRING;
-    where.buffer = const_cast<char*>(addr6.c_str());
-    where.buffer_length = addr6_length;
-    where.length = &addr6_length;
-    bind.push_back(where);
+    inbind[0].buffer_type = MYSQL_TYPE_STRING;
+    inbind[0].buffer = const_cast<char*>(addr6.c_str());
+    inbind[0].buffer_length = addr6_length;
+    inbind[0].length = &addr6_length;
+
+    bind.push_back(inbind[0]);
+
+    MYSQL_TIME expire;
+    MySqlConnection::convertToDatabaseTime(lease->old_cltt_, lease->old_valid_lft_,
+                                           expire);
+    inbind[1].buffer_type = MYSQL_TYPE_TIMESTAMP;
+    inbind[1].buffer = reinterpret_cast<char*>(&expire);
+    inbind[1].buffer_length = sizeof(expire);
+
+    bind.push_back(inbind[1]);
 
     // Drop to common update code
     updateLeaseCommon(ctx, stindex, &bind[0], lease);
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
 }
 
 // Delete lease methods.  Similar to other groups of methods, these comprise
@@ -2791,7 +2846,7 @@ MySqlLeaseMgr::deleteLease(const Lease4Ptr& lease) {
         .arg(addr.toText());
 
     // Set up the WHERE clause value
-    MYSQL_BIND inbind[1];
+    MYSQL_BIND inbind[2];
     memset(inbind, 0, sizeof(inbind));
 
     uint32_t addr4 = addr.toUint32();
@@ -2800,6 +2855,13 @@ MySqlLeaseMgr::deleteLease(const Lease4Ptr& lease) {
     inbind[0].buffer = reinterpret_cast<char*>(&addr4);
     inbind[0].is_unsigned = MLM_TRUE;
 
+    MYSQL_TIME expire;
+    MySqlConnection::convertToDatabaseTime(lease->old_cltt_, lease->old_valid_lft_,
+                                           expire);
+    inbind[1].buffer_type = MYSQL_TYPE_TIMESTAMP;
+    inbind[1].buffer = reinterpret_cast<char*>(&expire);
+    inbind[1].buffer_length = sizeof(expire);
+
     return (deleteLeaseCommon(DELETE_LEASE4, inbind) > 0);
 }
 
@@ -2811,7 +2873,7 @@ MySqlLeaseMgr::deleteLease(const Lease6Ptr& lease) {
         .arg(addr.toText());
 
     // Set up the WHERE clause value
-    MYSQL_BIND inbind[1];
+    MYSQL_BIND inbind[2];
     memset(inbind, 0, sizeof(inbind));
 
     std::string addr6 = addr.toText();
@@ -2824,6 +2886,13 @@ MySqlLeaseMgr::deleteLease(const Lease6Ptr& lease) {
     inbind[0].buffer_length = addr6_length;
     inbind[0].length = &addr6_length;
 
+    MYSQL_TIME expire;
+    MySqlConnection::convertToDatabaseTime(lease->old_cltt_, lease->old_valid_lft_,
+                                           expire);
+    inbind[1].buffer_type = MYSQL_TYPE_TIMESTAMP;
+    inbind[1].buffer = reinterpret_cast<char*>(&expire);
+    inbind[1].buffer_length = sizeof(expire);
+
     return (deleteLeaseCommon(DELETE_LEASE6, inbind) > 0);
 }
 
diff --git a/src/lib/dhcpsrv/mysql_lease_mgr.h b/src/lib/dhcpsrv/mysql_lease_mgr.h
index c638f5c8ce..2bfc1790ef 100644
--- a/src/lib/dhcpsrv/mysql_lease_mgr.h
+++ b/src/lib/dhcpsrv/mysql_lease_mgr.h
@@ -667,6 +667,7 @@ public:
     };
 
 private:
+
     /// @brief Add Lease Common Code
     ///
     /// This method performs the common actions for both flavours (V4 and V6)
@@ -899,6 +900,7 @@ private:
         MySqlLeaseContextPtr ctx_;
 
     private:
+
         /// @brief The manager
         const MySqlLeaseMgr& mgr_;
     };
diff --git a/src/lib/dhcpsrv/pgsql_lease_mgr.cc b/src/lib/dhcpsrv/pgsql_lease_mgr.cc
index 4306a9815e..a63830bfac 100644
--- a/src/lib/dhcpsrv/pgsql_lease_mgr.cc
+++ b/src/lib/dhcpsrv/pgsql_lease_mgr.cc
@@ -14,6 +14,7 @@
 #include <dhcpsrv/pgsql_lease_mgr.h>
 #include <util/multi_threading_mgr.h>
 
+#include <boost/make_shared.hpp>
 #include <boost/static_assert.hpp>
 
 #include <iomanip>
@@ -28,7 +29,6 @@ using namespace isc::db;
 using namespace isc::dhcp;
 using namespace isc::data;
 using namespace isc::util;
-using namespace std;
 
 namespace {
 
@@ -37,9 +37,9 @@ namespace {
 /// that the occur in the table.  This does not apply to the where clause.
 PgSqlTaggedStatement tagged_statements[] = {
     // DELETE_LEASE4
-    { 1, { OID_INT8 },
+    { 2, { OID_INT8, OID_TIMESTAMP },
       "delete_lease4",
-      "DELETE FROM lease4 WHERE address = $1"},
+      "DELETE FROM lease4 WHERE address = $1 AND expire = $2"},
 
     // DELETE_LEASE4_STATE_EXPIRED
     { 2, { OID_INT8, OID_TIMESTAMP },
@@ -48,9 +48,9 @@ PgSqlTaggedStatement tagged_statements[] = {
           "WHERE state = $1 AND expire < $2"},
 
     // DELETE_LEASE6
-    { 1, { OID_VARCHAR },
+    { 2, { OID_VARCHAR, OID_TIMESTAMP },
       "delete_lease6",
-      "DELETE FROM lease6 WHERE address = $1"},
+      "DELETE FROM lease6 WHERE address = $1 AND expire = $2"},
 
     // DELETE_LEASE6_STATE_EXPIRED
     { 2, { OID_INT8, OID_TIMESTAMP },
@@ -287,20 +287,20 @@ PgSqlTaggedStatement tagged_statements[] = {
       "VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16, $17)"},
 
     // UPDATE_LEASE4
-    { 12, { OID_INT8, OID_BYTEA, OID_BYTEA, OID_INT8, OID_TIMESTAMP, OID_INT8,
-            OID_BOOL, OID_BOOL, OID_VARCHAR, OID_INT8, OID_TEXT, OID_INT8 },
+    { 13, { OID_INT8, OID_BYTEA, OID_BYTEA, OID_INT8, OID_TIMESTAMP, OID_INT8,
+            OID_BOOL, OID_BOOL, OID_VARCHAR, OID_INT8, OID_TEXT, OID_INT8, OID_TIMESTAMP },
       "update_lease4",
       "UPDATE lease4 SET address = $1, hwaddr = $2, "
         "client_id = $3, valid_lifetime = $4, expire = $5, "
         "subnet_id = $6, fqdn_fwd = $7, fqdn_rev = $8, hostname = $9, "
         "state = $10, user_context = $11 "
-      "WHERE address = $12"},
+      "WHERE address = $12 AND expire = $13"},
 
     // UPDATE_LEASE6
-    { 18, { OID_VARCHAR, OID_BYTEA, OID_INT8, OID_TIMESTAMP, OID_INT8, OID_INT8,
+    { 19, { OID_VARCHAR, OID_BYTEA, OID_INT8, OID_TIMESTAMP, OID_INT8, OID_INT8,
             OID_INT2, OID_INT8, OID_INT2, OID_BOOL, OID_BOOL, OID_VARCHAR,
             OID_BYTEA, OID_INT2, OID_INT2,
-            OID_INT8, OID_TEXT, OID_VARCHAR },
+            OID_INT8, OID_TEXT, OID_VARCHAR, OID_TIMESTAMP },
       "update_lease6",
       "UPDATE lease6 SET address = $1, duid = $2, "
         "valid_lifetime = $3, expire = $4, subnet_id = $5, "
@@ -308,7 +308,7 @@ PgSqlTaggedStatement tagged_statements[] = {
         "prefix_len = $9, fqdn_fwd = $10, fqdn_rev = $11, hostname = $12, "
         "hwaddr = $13, hwtype = $14, hwaddr_source = $15, "
         "state = $16, user_context = $17 "
-      "WHERE address = $18"},
+      "WHERE address = $18 AND expire = $19"},
 
     // ALL_LEASE4_STATS
     { 0, { OID_NONE },
@@ -369,31 +369,37 @@ namespace dhcp {
 /// database.
 class PgSqlLeaseExchange : public PgSqlExchange {
 public:
+
     PgSqlLeaseExchange()
-        : addr_str_(""), valid_lifetime_(0), valid_lifetime_str_(""),
-          expire_(0), expire_str_(""), subnet_id_(0), subnet_id_str_(""),
-          cltt_(0), fqdn_fwd_(false), fqdn_rev_(false), hostname_(""),
-          state_str_(""), user_context_("") {
+        : addr_str_(""), hwaddr_length_(0), hwaddr_(hwaddr_length_),
+          valid_lifetime_(0), valid_lifetime_str_(""), expire_(0),
+          expire_str_(""), subnet_id_(0), subnet_id_str_(""), cltt_(0),
+          fqdn_fwd_(false), fqdn_rev_(false), hostname_(""), state_str_(""),
+          user_context_("") {
     }
 
     virtual ~PgSqlLeaseExchange(){}
 
 protected:
+
     /// @brief Common Instance members used for binding and conversion
     //@{
-    std::string            addr_str_;
-    uint32_t               valid_lifetime_;
-    std::string            valid_lifetime_str_;
-    time_t                 expire_;
-    std::string            expire_str_;
-    uint32_t               subnet_id_;
-    std::string            subnet_id_str_;
-    time_t                 cltt_;
-    bool                   fqdn_fwd_;
-    bool                   fqdn_rev_;
-    std::string            hostname_;
-    std::string            state_str_;
-    std::string            user_context_;
+    std::string          addr_str_;
+    size_t               hwaddr_length_;
+    std::vector<uint8_t> hwaddr_;
+    uint8_t              hwaddr_buffer_[HWAddr::MAX_HWADDR_LEN];
+    uint32_t             valid_lifetime_;
+    std::string          valid_lifetime_str_;
+    time_t               expire_;
+    std::string          expire_str_;
+    uint32_t             subnet_id_;
+    std::string          subnet_id_str_;
+    time_t               cltt_;
+    bool                 fqdn_fwd_;
+    bool                 fqdn_rev_;
+    std::string          hostname_;
+    std::string          state_str_;
+    std::string          user_context_;
     //@}
 };
 
@@ -423,8 +429,7 @@ public:
 
     /// @brief Constructor
     PgSqlLease4Exchange()
-        : lease_(), addr4_(0), hwaddr_length_(0), hwaddr_(hwaddr_length_),
-        client_id_length_(0) {
+        : lease_(), addr4_(0), client_id_length_(0) {
 
         BOOST_STATIC_ASSERT(9 < LEASE_COLUMNS);
 
@@ -466,8 +471,7 @@ public:
         lease_ = lease;
 
         try {
-            addr_str_ = boost::lexical_cast<std::string>
-                        (lease->addr_.toUint32());
+            addr_str_ = boost::lexical_cast<std::string>(lease->addr_.toUint32());
             bind_array.add(addr_str_);
 
             if (lease->hwaddr_ && !lease->hwaddr_->hwaddr_.empty()) {
@@ -521,7 +525,6 @@ public:
                 user_context_ = "";
             }
             bind_array.add(user_context_);
-
         } catch (const std::exception& ex) {
             isc_throw(DbOperationError,
                       "Could not create bind array from Lease4: "
@@ -583,12 +586,12 @@ public:
                 }
             }
 
-            Lease4Ptr result(new Lease4(addr4_, hwaddr,
-                                        client_id_buffer_,
-                                        client_id_length_,
-                                        valid_lifetime_, cltt_,
-                                        subnet_id_, fqdn_fwd_,
-                                        fqdn_rev_, hostname_));
+            Lease4Ptr result(boost::make_shared<Lease4>(addr4_, hwaddr,
+                                                        client_id_buffer_,
+                                                        client_id_length_,
+                                                        valid_lifetime_, cltt_,
+                                                        subnet_id_, fqdn_fwd_,
+                                                        fqdn_rev_, hostname_));
 
             result->state_ = state;
 
@@ -605,18 +608,16 @@ public:
     }
 
 private:
+
     /// @brief Lease4 object currently being sent to the database.
     /// Storing this value ensures that it remains in scope while any bindings
     /// that refer to its contents are in use.
     Lease4Ptr              lease_;
 
     /// @brief Lease4 specific members for binding and conversion.
-    uint32_t               addr4_;
-    size_t                 hwaddr_length_;
-    std::vector<uint8_t>   hwaddr_;
-    uint8_t                hwaddr_buffer_[HWAddr::MAX_HWADDR_LEN];
-    size_t                 client_id_length_;
-    uint8_t                client_id_buffer_[ClientId::MAX_CLIENT_ID_LEN];
+    uint32_t addr4_;
+    size_t   client_id_length_;
+    uint8_t  client_id_buffer_[ClientId::MAX_CLIENT_ID_LEN];
 };
 
 /// @brief Supports exchanging IPv6 leases with PostgreSQL.
@@ -676,9 +677,11 @@ public:
     };
 
     PgSqlLease6Exchange()
-        : lease_(), duid_length_(0), duid_(), iaid_u_(0), iaid_str_(""),
-          lease_type_(Lease6::TYPE_NA), lease_type_str_(""), prefix_len_(0),
-          prefix_len_str_(""), pref_lifetime_(0), preferred_lifetime_str_("") {
+        : lease_(), duid_length_(0), duid_(duid_length_), iaid_u_(0),
+          iaid_str_(""), lease_type_(Lease6::TYPE_NA), lease_type_str_(""),
+          prefix_len_(0), prefix_len_str_(""), pref_lifetime_(0),
+          preferred_lifetime_str_(""), hwtype_(0), hwtype_str_(""),
+          hwaddr_source_(0), hwaddr_source_str_("") {
 
         BOOST_STATIC_ASSERT(15 < LEASE_COLUMNS);
 
@@ -761,8 +764,7 @@ public:
             iaid_str_ = iaid_u_.dbInputString();
             bind_array.add(iaid_str_);
 
-            prefix_len_str_ = boost::lexical_cast<std::string>
-                              (static_cast<unsigned int>(lease_->prefixlen_));
+            prefix_len_str_ = boost::lexical_cast<std::string>(static_cast<unsigned int>(lease_->prefixlen_));
             bind_array.add(prefix_len_str_);
 
             bind_array.add(lease->fqdn_fwd_);
@@ -786,15 +788,12 @@ public:
             }
 
             if (lease->hwaddr_) {
-                hwtype_str_ = boost::lexical_cast<std::string>
-                              (static_cast<unsigned int>(lease_->hwaddr_->htype_));
+                hwtype_str_ = boost::lexical_cast<std::string>(static_cast<unsigned int>(lease_->hwaddr_->htype_));
                 hwaddr_source_str_ = boost::lexical_cast<std::string>
                                      (static_cast<unsigned int>(lease_->hwaddr_->source_));
             } else {
-                hwtype_str_ = boost::lexical_cast<std::string>
-                              (static_cast<unsigned int>(HTYPE_UNDEFINED));
-                hwaddr_source_str_ = boost::lexical_cast<std::string>
-                                     (static_cast<unsigned int>(HWAddr::HWADDR_SOURCE_UNKNOWN));
+                hwtype_str_ = boost::lexical_cast<std::string>(static_cast<unsigned int>(HTYPE_UNDEFINED));
+                hwaddr_source_str_ = boost::lexical_cast<std::string>(static_cast<unsigned int>(HWAddr::HWADDR_SOURCE_UNKNOWN));
             }
 
             bind_array.add(hwtype_str_);
@@ -811,7 +810,6 @@ public:
                 user_context_ = "";
             }
             bind_array.add(user_context_);
-
         } catch (const std::exception& ex) {
             isc_throw(DbOperationError,
                       "Could not create bind array from Lease6: "
@@ -900,12 +898,16 @@ public:
                 }
             }
 
-            Lease6Ptr result(new Lease6(lease_type_, addr, duid_ptr,
-                                        iaid_u_.uval_, pref_lifetime_,
-                                        valid_lifetime_,
-                                        subnet_id_, fqdn_fwd_, fqdn_rev_,
-                                        hostname_, hwaddr, prefix_len_));
+            Lease6Ptr result(boost::make_shared<Lease6>(lease_type_, addr,
+                                                        duid_ptr,
+                                                        iaid_u_.uval_,
+                                                        pref_lifetime_,
+                                                        valid_lifetime_,
+                                                        subnet_id_, fqdn_fwd_,
+                                                        fqdn_rev_, hostname_,
+                                                        hwaddr, prefix_len_));
             result->cltt_ = cltt_;
+            result->old_cltt_ = cltt_;
 
             result->state_ = state;
 
@@ -958,24 +960,21 @@ private:
 
     /// @brief Lease6 specific members for binding and conversion.
     //@{
-    size_t                 duid_length_;
-    vector<uint8_t>        duid_;
-    uint8_t                duid_buffer_[DUID::MAX_DUID_LEN];
-    union Uiaid            iaid_u_;
-    std::string            iaid_str_;
-    Lease6::Type           lease_type_;
-    std::string            lease_type_str_;
-    uint8_t                prefix_len_;
-    std::string            prefix_len_str_;
-    uint32_t               pref_lifetime_;
-    std::string            preferred_lifetime_str_;
-    size_t                 hwaddr_length_;
-    vector<uint8_t>        hwaddr_;
-    uint8_t                hwaddr_buffer_[HWAddr::MAX_HWADDR_LEN];
-    uint32_t               hwtype_;
-    std::string            hwtype_str_;
-    uint32_t               hwaddr_source_;
-    std::string            hwaddr_source_str_;
+    size_t               duid_length_;
+    std::vector<uint8_t> duid_;
+    uint8_t              duid_buffer_[DUID::MAX_DUID_LEN];
+    union Uiaid          iaid_u_;
+    std::string          iaid_str_;
+    Lease6::Type         lease_type_;
+    std::string          lease_type_str_;
+    uint8_t              prefix_len_;
+    std::string          prefix_len_str_;
+    uint32_t             pref_lifetime_;
+    std::string          preferred_lifetime_str_;
+    uint32_t             hwtype_;
+    std::string          hwtype_str_;
+    uint32_t             hwaddr_source_;
+    std::string          hwaddr_source_str_;
     //@}
 };
 
@@ -986,6 +985,7 @@ private:
 ///
 class PgSqlLeaseStatsQuery : public LeaseStatsQuery {
 public:
+
     /// @brief Constructor to query for all subnets' stats
     ///
     ///  The query created will return statistics for all subnets
@@ -1060,7 +1060,7 @@ public:
             // Add last_subnet_id for range.
             if (getSelectMode() == SUBNET_RANGE) {
                 // Add last_subnet_id used by range.
-                string subnet_id_str = boost::lexical_cast<std::string>(getLastSubnetID());
+                std::string subnet_id_str = boost::lexical_cast<std::string>(getLastSubnetID());
                 parms.add(subnet_id_str);
             }
 
@@ -1123,6 +1123,7 @@ public:
     }
 
 protected:
+
     /// @brief Database connection to use to execute the query
     PgSqlConnection& conn_;
 
@@ -1179,7 +1180,7 @@ PgSqlLeaseMgr::PgSqlLeaseContextAlloc::~PgSqlLeaseContextAlloc() {
 // PgSqlLeaseMgr Constructor and Destructor
 
 PgSqlLeaseMgr::PgSqlLeaseMgr(const DatabaseConnection::ParameterMap& parameters)
-    : LeaseMgr(), parameters_(parameters) {
+    : parameters_(parameters) {
 
     // Validate schema version first.
     std::pair<uint32_t, uint32_t> code_version(PG_SCHEMA_VERSION_MAJOR,
@@ -1276,7 +1277,12 @@ PgSqlLeaseMgr::addLease(const Lease4Ptr& lease) {
 
     PsqlBindArray bind_array;
     ctx->exchange4_->createBindForSend(lease, bind_array);
-    return (addLeaseCommon(ctx, INSERT_LEASE4, bind_array));
+    auto result = addLeaseCommon(ctx, INSERT_LEASE4, bind_array);
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
+
+    return (result);
 }
 
 bool
@@ -1292,16 +1298,22 @@ PgSqlLeaseMgr::addLease(const Lease6Ptr& lease) {
     PsqlBindArray bind_array;
     ctx->exchange6_->createBindForSend(lease, bind_array);
 
-    return (addLeaseCommon(ctx, INSERT_LEASE6, bind_array));
+    auto result = addLeaseCommon(ctx, INSERT_LEASE6, bind_array);
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
+
+    return (result);
 }
 
 template <typename Exchange, typename LeaseCollection>
-void PgSqlLeaseMgr::getLeaseCollection(PgSqlLeaseContextPtr ctx,
-                                       StatementIndex stindex,
-                                       PsqlBindArray& bind_array,
-                                       Exchange& exchange,
-                                       LeaseCollection& result,
-                                       bool single) const {
+void
+PgSqlLeaseMgr::getLeaseCollection(PgSqlLeaseContextPtr ctx,
+                                  StatementIndex stindex,
+                                  PsqlBindArray& bind_array,
+                                  Exchange& exchange,
+                                  LeaseCollection& result,
+                                  bool single) const {
     const int n = tagged_statements[stindex].nbparams;
     PgSqlResult r(PQexecPrepared(ctx->conn_,
                                  tagged_statements[stindex].name, n,
@@ -1374,8 +1386,7 @@ PgSqlLeaseMgr::getLease4(const isc::asiolink::IOAddress& addr) const {
     PsqlBindArray bind_array;
 
     // LEASE ADDRESS
-    std::string addr_str = boost::lexical_cast<std::string>
-                           (addr.toUint32());
+    std::string addr_str = boost::lexical_cast<std::string>(addr.toUint32());
     bind_array.add(addr_str);
 
     // Get the data
@@ -1593,8 +1604,7 @@ PgSqlLeaseMgr::getLeases4(const asiolink::IOAddress& lower_bound_address,
     PsqlBindArray bind_array;
 
     // Bind lower bound address
-    std::string lb_address_data = boost::lexical_cast<std::string>
-        (lower_bound_address.toUint32());
+    std::string lb_address_data = boost::lexical_cast<std::string>(lower_bound_address.toUint32());
     bind_array.add(lb_address_data);
 
     // Bind page size value
@@ -1866,8 +1876,8 @@ PgSqlLeaseMgr::getExpiredLeases6(Lease6Collection& expired_leases,
 template<typename LeaseCollection>
 void
 PgSqlLeaseMgr::getExpiredLeasesCommon(LeaseCollection& expired_leases,
-                                       const size_t max_leases,
-                                       StatementIndex statement_index) const {
+                                      const size_t max_leases,
+                                      StatementIndex statement_index) const {
     PsqlBindArray bind_array;
 
     // Exclude reclaimed leases.
@@ -1923,7 +1933,7 @@ PgSqlLeaseMgr::updateLeaseCommon(PgSqlLeaseContextPtr ctx,
     // Should not happen - primary key constraint should only have selected
     // one row.
     isc_throw(DbOperationError, "apparently updated more than one lease "
-                  "that had the address " << lease->addr_.toText());
+              "that had the address " << lease->addr_.toText());
 }
 
 void
@@ -1945,8 +1955,15 @@ PgSqlLeaseMgr::updateLease4(const Lease4Ptr& lease) {
     std::string addr4_str = boost::lexical_cast<std::string>(lease->addr_.toUint32());
     bind_array.add(addr4_str);
 
+    std::string expire_str = PgSqlLeaseExchange::convertToDatabaseTime(lease->old_cltt_,
+                                                                       lease->old_valid_lft_);
+    bind_array.add(expire_str);
+
     // Drop to common update code
     updateLeaseCommon(ctx, stindex, bind_array, lease);
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
 }
 
 void
@@ -1969,8 +1986,15 @@ PgSqlLeaseMgr::updateLease6(const Lease6Ptr& lease) {
     std::string addr_str = lease->addr_.toText();
     bind_array.add(addr_str);
 
+    std::string expire_str = PgSqlLeaseExchange::convertToDatabaseTime(lease->old_cltt_,
+                                                                       lease->old_valid_lft_);
+    bind_array.add(expire_str);
+
     // Drop to common update code
     updateLeaseCommon(ctx, stindex, bind_array, lease);
+
+    lease->old_cltt_ = lease->cltt_;
+    lease->old_valid_lft_ = lease->valid_lft_;
 }
 
 uint64_t
@@ -2003,6 +2027,11 @@ PgSqlLeaseMgr::deleteLease(const Lease4Ptr& lease) {
 
     std::string addr4_str = boost::lexical_cast<std::string>(addr.toUint32());
     bind_array.add(addr4_str);
+
+    std::string expire_str = PgSqlLeaseExchange::convertToDatabaseTime(lease->old_cltt_,
+                                                                       lease->old_valid_lft_);
+    bind_array.add(expire_str);
+
     return (deleteLeaseCommon(DELETE_LEASE4, bind_array) > 0);
 }
 
@@ -2018,6 +2047,11 @@ PgSqlLeaseMgr::deleteLease(const Lease6Ptr& lease) {
 
     std::string addr6_str = addr.toText();
     bind_array.add(addr6_str);
+
+    std::string expire_str = PgSqlLeaseExchange::convertToDatabaseTime(lease->old_cltt_,
+                                                                       lease->old_valid_lft_);
+    bind_array.add(expire_str);
+
     return (deleteLeaseCommon(DELETE_LEASE6, bind_array) > 0);
 }
 
@@ -2045,8 +2079,7 @@ PgSqlLeaseMgr::deleteExpiredReclaimedLeasesCommon(const uint32_t secs,
     bind_array.add(state_str);
 
     // Expiration timestamp.
-    std::string expiration_str =
-        PgSqlLeaseExchange::convertToDatabaseTime(time(NULL) - static_cast<time_t>(secs));
+    std::string expiration_str = PgSqlLeaseExchange::convertToDatabaseTime(time(NULL) - static_cast<time_t>(secs));
     bind_array.add(expiration_str);
 
     // Delete leases.
diff --git a/src/lib/dhcpsrv/pgsql_lease_mgr.h b/src/lib/dhcpsrv/pgsql_lease_mgr.h
index 5a7489e870..834584612c 100644
--- a/src/lib/dhcpsrv/pgsql_lease_mgr.h
+++ b/src/lib/dhcpsrv/pgsql_lease_mgr.h
@@ -642,6 +642,7 @@ public:
     };
 
 private:
+
     /// @brief Add Lease Common Code
     ///
     /// This method performs the common actions for both flavours (V4 and V6)
@@ -857,6 +858,7 @@ private:
         PgSqlLeaseContextPtr ctx_;
 
     private:
+
         /// @brief The manager
         const PgSqlLeaseMgr& mgr_;
     };
diff --git a/src/lib/dhcpsrv/tests/generic_lease_mgr_unittest.cc b/src/lib/dhcpsrv/tests/generic_lease_mgr_unittest.cc
index 4f1231928a..681ff966b0 100644
--- a/src/lib/dhcpsrv/tests/generic_lease_mgr_unittest.cc
+++ b/src/lib/dhcpsrv/tests/generic_lease_mgr_unittest.cc
@@ -1923,13 +1923,13 @@ GenericLeaseMgrTest::testRecreateLease4() {
     Lease4Ptr lease(new Lease4(*leases[0]));
 
     // Add a lease.
-    EXPECT_TRUE(lmptr_->addLease(lease));
+    EXPECT_TRUE(lmptr_->addLease(leases[0]));
     lmptr_->commit();
 
     // Check that the lease has been successfully added.
     Lease4Ptr l_returned = lmptr_->getLease4(ioaddress4_[0]);
     ASSERT_TRUE(l_returned);
-    detailCompareLease(lease, l_returned);
+    detailCompareLease(leases[0], l_returned);
 
     // Delete a lease, check that it's gone.
     EXPECT_TRUE(lmptr_->deleteLease(leases[0]));
@@ -1963,13 +1963,13 @@ GenericLeaseMgrTest::testRecreateLease6() {
     Lease6Ptr lease(new Lease6(*leases[0]));
 
     // Add a lease.
-    EXPECT_TRUE(lmptr_->addLease(lease));
+    EXPECT_TRUE(lmptr_->addLease(leases[0]));
     lmptr_->commit();
 
     // Check that the lease has been successfully added.
     Lease6Ptr l_returned = lmptr_->getLease6(Lease::TYPE_NA, ioaddress6_[0]);
     ASSERT_TRUE(l_returned);
-    detailCompareLease(lease, l_returned);
+    detailCompareLease(leases[0], l_returned);
 
     // Delete a lease, check that it's gone.
     EXPECT_TRUE(lmptr_->deleteLease(leases[0]));