diff --git a/LICENSE.md b/LICENSE.md
index 02fb6137f..6c4ae305a 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -323,7 +323,7 @@ The embedded copy of zlib bears the following license:
 
 The embedded copy of protobuf-c bears the following license:
 
-    Copyright (c) 2008-2022, Dave Benson and the protobuf-c authors.
+    Copyright (c) 2008-2025, Dave Benson and the protobuf-c authors.
     All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
diff --git a/include/protobuf-c/protobuf-c.h b/include/protobuf-c/protobuf-c.h
index 442abf61d..54aca51f8 100644
--- a/include/protobuf-c/protobuf-c.h
+++ b/include/protobuf-c/protobuf-c.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2022, Dave Benson and the protobuf-c authors.
+ * Copyright (c) 2008-2025, Dave Benson and the protobuf-c authors.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -34,16 +34,17 @@
  *
  * This file defines the public API for the `libprotobuf-c` support library.
  * This API includes interfaces that can be used directly by client code as well
- * as the interfaces used by the code generated by the `protoc-c` compiler.
+ * as the interfaces used by the code generated by the `protoc-gen-c` compiler
+ * plugin.
  *
  * The `libprotobuf-c` support library performs the actual serialization and
  * deserialization of Protocol Buffers messages. It interacts with structures,
- * definitions, and metadata generated by the `protoc-c` compiler from .proto
- * files.
+ * definitions, and metadata generated by the `protoc-gen-c` compiler plugin
+ * from .proto files.
  *
  * \authors Dave Benson and the `protobuf-c` authors.
  *
- * \copyright 2008-2014. Licensed under the terms of the [BSD-2-Clause] license.
+ * \copyright 2008-2025. Licensed under the terms of the [BSD-2-Clause] license.
  *
  * [protobuf-c]:       https://github.com/protobuf-c/protobuf-c
  * [Protocol Buffers]: https://developers.google.com/protocol-buffers/
@@ -74,7 +75,7 @@
  *
  * - Identifiers for functions and globals are all lowercase, with camel case
  *   words separated by single underscores. For example, one of the function
- *   prototypes generated by `protoc-c` for the above example:
+ *   prototypes generated by `protoc-gen-c` for the above example:
  *
 ~~~{.c}
 Foo__Bar__BazBah *
@@ -794,16 +795,16 @@ protobuf_c_version_number(void);
  * The version of the protobuf-c headers, represented as a string using the same
  * format as protobuf_c_version().
  */
-#define PROTOBUF_C_VERSION		"1.4.1"
+#define PROTOBUF_C_VERSION		"1.5.2"
 
 /**
  * The version of the protobuf-c headers, represented as an integer using the
  * same format as protobuf_c_version_number().
  */
-#define PROTOBUF_C_VERSION_NUMBER	1004001
+#define PROTOBUF_C_VERSION_NUMBER	1005002
 
 /**
- * The minimum protoc-c version which works with the current version of the
+ * The minimum protoc-gen-c version which works with the current version of the
  * protobuf-c headers.
  */
 #define PROTOBUF_C_MIN_COMPILER_VERSION	1000000
diff --git a/lib/logsrv/Makefile.in b/lib/logsrv/Makefile.in
index f4e29af7c..88a3dfb27 100644
--- a/lib/logsrv/Makefile.in
+++ b/lib/logsrv/Makefile.in
@@ -108,7 +108,7 @@ Makefile: $(srcdir)/Makefile.in
 
 $(devdir)/log_server.pb-c.c: $(srcdir)/log_server.proto
 	@if [ -n "$(DEVEL)" ]; then \
-	    cmd='protoc-c --c_out=$(devdir) --proto_path=$(srcdir) $(srcdir)/log_server.proto'; \
+	    cmd='protoc --c_out=$(devdir) --proto_path=$(srcdir) $(srcdir)/log_server.proto'; \
 	    echo "$$cmd"; eval $$cmd; \
 	    cmd='$(scriptdir)/unanon $(devdir)/log_server.pb-c.h $(devdir)/log_server.pb-c.c'; \
 	    echo "$$cmd"; eval $$cmd; \
diff --git a/lib/protobuf-c/Makefile.in b/lib/protobuf-c/Makefile.in
index 82a9e2896..8701047e1 100644
--- a/lib/protobuf-c/Makefile.in
+++ b/lib/protobuf-c/Makefile.in
@@ -101,20 +101,6 @@ Makefile: $(srcdir)/Makefile.in
 .i.plog:
 	ifile=$<; rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $${ifile%i}c --i-file $< --output-file $@
 
-$(devdir)/log_server.pb-c.c: $(srcdir)/log_server.proto
-	@if [ -n "$(DEVEL)" ]; then \
-	    cmd='protoc-c --c_out=$(devdir) --proto_path=$(srcdir) $(srcdir)/log_server.proto'; \
-	    echo "$$cmd"; eval $$cmd; \
-	    cmd='$(scriptdir)/unanon $(devdir)/log_server.pb-c.h $(devdir)/log_server.pb-c.c'; \
-	    echo "$$cmd"; eval $$cmd; \
-	    if [ "$(devdir)" == "$(srcdir)" ]; then \
-		cmd='mv -f $(devdir)/log_server.pb-c.h $(incdir)/log_server.pb-c.h'; \
-	    else \
-		cmd='mv -f $(devdir)/log_server.pb-c.h $(top_builddir)/log_server.pb-c.h'; \
-	    fi; \
-	    echo "$$cmd"; eval $$cmd; \
-	fi
-
 libprotobuf-c.la: $(LIBPROTOBUF_C_OBJS)
 	$(LIBTOOL) $(LTFLAGS) --mode=link $(CC) -o $@ $(LIBPROTOBUF_C_OBJS)
 
diff --git a/lib/protobuf-c/protobuf-c.c b/lib/protobuf-c/protobuf-c.c
index 9d7da2681..0521b94cf 100644
--- a/lib/protobuf-c/protobuf-c.c
+++ b/lib/protobuf-c/protobuf-c.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2022, Dave Benson and the protobuf-c authors.
+ * Copyright (c) 2008-2025, Dave Benson and the protobuf-c authors.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -28,14 +28,14 @@
  */
 
 /*! \file
- * Support library for `protoc-c` generated code.
+ * Support library for `protoc-gen-c` generated code.
  *
  * This file implements the public API used by the code generated
- * by `protoc-c`.
+ * by `protoc-gen-c`.
  *
  * \authors Dave Benson and the protobuf-c authors
  *
- * \copyright 2008-2014. Licensed under the terms of the [BSD-2-Clause] license.
+ * \copyright 2008-2025. Licensed under the terms of the [BSD-2-Clause] license.
  */
 
 /**
@@ -1903,7 +1903,6 @@ pack_buffer_packed_payload(const ProtobufCFieldDescriptor *field,
 		for (i = 0; i < count; i++) {
 			unsigned len = boolean_pack(((protobuf_c_boolean *) array)[i], scratch);
 			buffer->append(buffer, len, scratch);
-			rv += len;
 		}
 		return count;
 	default:
@@ -1938,6 +1937,7 @@ repeated_field_pack_to_buffer(const ProtobufCFieldDescriptor *field,
 		buffer->append(buffer, rv, scratch);
 		tmp = pack_buffer_packed_payload(field, count, array, buffer);
 		assert(tmp == payload_len);
+		(void)tmp;
 		return rv + payload_len;
 	} else {
 		size_t siz;
@@ -2571,7 +2571,7 @@ parse_required_member(ScannedMember *scanned_member,
 
 		if (maybe_clear && *pstr != NULL) {
 			const char *def = scanned_member->field->default_value;
-			if (*pstr != NULL && *pstr != def)
+			if (*pstr != def)
 				do_free(allocator, *pstr);
 		}
 		*pstr = do_alloc(allocator, len - pref_len + 1);
@@ -3293,6 +3293,8 @@ protobuf_c_message_unpack(const ProtobufCMessageDescriptor *desc,
 					      n_unknown * sizeof(ProtobufCMessageUnknownField));
 		if (rv->unknown_fields == NULL)
 			goto error_cleanup;
+	} else {
+		rv->unknown_fields = NULL;
 	}
 
 	/* do real parsing */
diff --git a/lib/ssl_compat/Makefile.in b/lib/ssl_compat/Makefile.in
index 7cc7dd083..0b95f71d7 100644
--- a/lib/ssl_compat/Makefile.in
+++ b/lib/ssl_compat/Makefile.in
@@ -106,20 +106,6 @@ Makefile: $(srcdir)/Makefile.in
 .i.plog:
 	ifile=$<; rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $${ifile%i}c --i-file $< --output-file $@
 
-$(devdir)/log_server.pb-c.c: $(srcdir)/log_server.proto
-	@if [ -n "$(DEVEL)" ]; then \
-	    cmd='protoc-c --c_out=$(devdir) --proto_path=$(srcdir) $(srcdir)/log_server.proto'; \
-	    echo "$$cmd"; eval $$cmd; \
-	    cmd='$(scriptdir)/unanon $(devdir)/log_server.pb-c.h $(devdir)/log_server.pb-c.c'; \
-	    echo "$$cmd"; eval $$cmd; \
-	    if [ "$(devdir)" == "$(srcdir)" ]; then \
-		cmd='mv -f $(devdir)/log_server.pb-c.h $(incdir)/log_server.pb-c.h'; \
-	    else \
-		cmd='mv -f $(devdir)/log_server.pb-c.h $(top_builddir)/log_server.pb-c.h'; \
-	    fi; \
-	    echo "$$cmd"; eval $$cmd; \
-	fi
-
 libssl_compat.la: $(LIBSSL_COMPAT_OBJS) $(LT_LIBS)
 	$(LIBTOOL) $(LTFLAGS) --mode=link $(CC) -o $@ $(LIBSSL_COMPAT_OBJS) $(LT_LIBS)
 
diff --git a/scripts/unanon b/scripts/unanon
index 2bbb3c856..4dc57bd2a 100755
--- a/scripts/unanon
+++ b/scripts/unanon
@@ -1,6 +1,6 @@
 #!/usr/bin/env perl
 #
-# Post-process files generated by protoc-c to remove anonymous unions.
+# Post-process files generated by protoc to remove anonymous unions.
 # Works on the generated files but probably little else.
 
 use warnings;
diff --git a/src/Makefile.in b/src/Makefile.in
index bc1ac461f..61f87caf4 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -203,7 +203,7 @@ Makefile: $(srcdir)/Makefile.in
 
 $(devdir)/intercept.pb-c.c: $(srcdir)/intercept.proto
 	@if [ -n "$(DEVEL)" ]; then \
-	    cmd='protoc-c --c_out=$(devdir) --proto_path=$(srcdir) $(srcdir)/intercept.proto'; \
+	    cmd='protoc --c_out=$(devdir) --proto_path=$(srcdir) $(srcdir)/intercept.proto'; \
 	    echo "$$cmd"; eval $$cmd; \
 	    cmd='$(scriptdir)/unanon $(devdir)/intercept.pb-c.h $(devdir)/intercept.pb-c.c'; \
 	    echo "$$cmd"; eval $$cmd; \
diff --git a/src/intercept.pb-c.c b/src/intercept.pb-c.c
index 2c58e6937..08175cfd8 100644
--- a/src/intercept.pb-c.c
+++ b/src/intercept.pb-c.c
@@ -378,7 +378,7 @@ static const ProtobufCFieldDescriptor intercept_request__field_descriptors[2] =
     offsetof(InterceptRequest, u.policy_check_req),
     &policy_check_request__descriptor,
     NULL,
-    0 | PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
+    PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
     0,NULL,NULL    /* reserved1,reserved2, etc */
   },
   {
@@ -390,7 +390,7 @@ static const ProtobufCFieldDescriptor intercept_request__field_descriptors[2] =
     offsetof(InterceptRequest, u.hello),
     &intercept_hello__descriptor,
     NULL,
-    0 | PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
+    PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
     0,NULL,NULL    /* reserved1,reserved2, etc */
   },
 };
@@ -774,7 +774,7 @@ static const ProtobufCFieldDescriptor intercept_response__field_descriptors[4] =
     offsetof(InterceptResponse, u.hello_resp),
     &hello_response__descriptor,
     NULL,
-    0 | PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
+    PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
     0,NULL,NULL    /* reserved1,reserved2, etc */
   },
   {
@@ -786,7 +786,7 @@ static const ProtobufCFieldDescriptor intercept_response__field_descriptors[4] =
     offsetof(InterceptResponse, u.accept_msg),
     &policy_accept_message__descriptor,
     NULL,
-    0 | PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
+    PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
     0,NULL,NULL    /* reserved1,reserved2, etc */
   },
   {
@@ -798,7 +798,7 @@ static const ProtobufCFieldDescriptor intercept_response__field_descriptors[4] =
     offsetof(InterceptResponse, u.reject_msg),
     &policy_reject_message__descriptor,
     NULL,
-    0 | PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
+    PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
     0,NULL,NULL    /* reserved1,reserved2, etc */
   },
   {
@@ -810,7 +810,7 @@ static const ProtobufCFieldDescriptor intercept_response__field_descriptors[4] =
     offsetof(InterceptResponse, u.error_msg),
     &policy_error_message__descriptor,
     NULL,
-    0 | PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
+    PROTOBUF_C_FIELD_FLAG_ONEOF,             /* flags */
     0,NULL,NULL    /* reserved1,reserved2, etc */
   },
 };