diff --git a/src/lib/dhcpsrv/libdhcpsrv.dox b/src/lib/dhcpsrv/libdhcpsrv.dox
index 6024ae6590..01872fd9d2 100644
--- a/src/lib/dhcpsrv/libdhcpsrv.dox
+++ b/src/lib/dhcpsrv/libdhcpsrv.dox
@@ -478,4 +478,6 @@ for configuration are not thread safe. Exceptions are:
 
  - last allocated members of subnets are Kea thread safe.
 
+ - timer manager functions are Kea thread safe.
+
 */