diff --git a/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs b/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs
new file mode 100644
index 0000000000..208ce1fcb6
--- /dev/null
+++ b/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs
@@ -0,0 +1,17 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+#endregion
+
+namespace Google.Protobuf.Reflection;
+
+internal sealed partial class FeatureSetDescriptor
+{
+    // Canonical serialized form of the edition defaults, generated by embed_edition_defaults.
+    private const string DefaultsBase64 =
+        "ChMYhAciACoMCAEQAhgCIAMoATACChMY5wciACoMCAIQARgBIAIoATABChMY6AciDAgBEAEYASACKAEwASoAIOYHKOgH";
+}
diff --git a/php/ext/google/protobuf/php-upb.c b/php/ext/google/protobuf/php-upb.c
index ca2718562a..924ea5be6c 100644
--- a/php/ext/google/protobuf/php-upb.c
+++ b/php/ext/google/protobuf/php-upb.c
@@ -60,6 +60,15 @@ Error, UINTPTR_MAX is undefined
  */
 #define UPB_PTR_AT(msg, ofs, type) ((type*)((char*)(msg) + (ofs)))
 
+// A flexible array member may have lower alignment requirements than the struct
+// overall - in that case, it can overlap with the trailing padding of the rest
+// of the struct, and a naive sizeof(base) + sizeof(flex) * count calculation
+// will not take into account that overlap, and allocate more than is required.
+#define UPB_SIZEOF_FLEX(type, member, count) \
+  (UPB_MAX(sizeof(type),                     \
+           (offsetof(type, member) +         \
+            count * (offsetof(type, member[1]) - offsetof(type, member[0])))))
+
 #define UPB_MAPTYPE_STRING 0
 
 // UPB_EXPORT: always generate a public symbol.
@@ -4935,7 +4944,7 @@ typedef struct {
 } upb_MdEnumDecoder;
 
 static size_t upb_MiniTableEnum_Size(size_t count) {
-  return sizeof(upb_MiniTableEnum) + count * sizeof(uint32_t);
+  return UPB_SIZEOF_FLEX(upb_MiniTableEnum, UPB_PRIVATE(data), count);
 }
 
 static upb_MiniTableEnum* _upb_MiniTable_AddEnumDataMember(upb_MdEnumDecoder* d,
@@ -17297,6 +17306,7 @@ upb_ServiceDef* _upb_ServiceDefs_New(upb_DefBuilder* ctx, int n,
 
 #undef UPB_SIZE
 #undef UPB_PTR_AT
+#undef UPB_SIZEOF_FLEX
 #undef UPB_MAPTYPE_STRING
 #undef UPB_EXPORT
 #undef UPB_INLINE
diff --git a/php/ext/google/protobuf/php-upb.h b/php/ext/google/protobuf/php-upb.h
index dada045adf..4247c132a8 100644
--- a/php/ext/google/protobuf/php-upb.h
+++ b/php/ext/google/protobuf/php-upb.h
@@ -59,6 +59,15 @@ Error, UINTPTR_MAX is undefined
  */
 #define UPB_PTR_AT(msg, ofs, type) ((type*)((char*)(msg) + (ofs)))
 
+// A flexible array member may have lower alignment requirements than the struct
+// overall - in that case, it can overlap with the trailing padding of the rest
+// of the struct, and a naive sizeof(base) + sizeof(flex) * count calculation
+// will not take into account that overlap, and allocate more than is required.
+#define UPB_SIZEOF_FLEX(type, member, count) \
+  (UPB_MAX(sizeof(type),                     \
+           (offsetof(type, member) +         \
+            count * (offsetof(type, member[1]) - offsetof(type, member[0])))))
+
 #define UPB_MAPTYPE_STRING 0
 
 // UPB_EXPORT: always generate a public symbol.
@@ -15528,6 +15537,7 @@ upb_MethodDef* _upb_MethodDefs_New(upb_DefBuilder* ctx, int n,
 
 #undef UPB_SIZE
 #undef UPB_PTR_AT
+#undef UPB_SIZEOF_FLEX
 #undef UPB_MAPTYPE_STRING
 #undef UPB_EXPORT
 #undef UPB_INLINE
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.c b/ruby/ext/google/protobuf_c/ruby-upb.c
index 0cb8b441da..af4351e444 100644
--- a/ruby/ext/google/protobuf_c/ruby-upb.c
+++ b/ruby/ext/google/protobuf_c/ruby-upb.c
@@ -60,6 +60,15 @@ Error, UINTPTR_MAX is undefined
  */
 #define UPB_PTR_AT(msg, ofs, type) ((type*)((char*)(msg) + (ofs)))
 
+// A flexible array member may have lower alignment requirements than the struct
+// overall - in that case, it can overlap with the trailing padding of the rest
+// of the struct, and a naive sizeof(base) + sizeof(flex) * count calculation
+// will not take into account that overlap, and allocate more than is required.
+#define UPB_SIZEOF_FLEX(type, member, count) \
+  (UPB_MAX(sizeof(type),                     \
+           (offsetof(type, member) +         \
+            count * (offsetof(type, member[1]) - offsetof(type, member[0])))))
+
 #define UPB_MAPTYPE_STRING 0
 
 // UPB_EXPORT: always generate a public symbol.
@@ -4935,7 +4944,7 @@ typedef struct {
 } upb_MdEnumDecoder;
 
 static size_t upb_MiniTableEnum_Size(size_t count) {
-  return sizeof(upb_MiniTableEnum) + count * sizeof(uint32_t);
+  return UPB_SIZEOF_FLEX(upb_MiniTableEnum, UPB_PRIVATE(data), count);
 }
 
 static upb_MiniTableEnum* _upb_MiniTable_AddEnumDataMember(upb_MdEnumDecoder* d,
@@ -16784,6 +16793,7 @@ upb_ServiceDef* _upb_ServiceDefs_New(upb_DefBuilder* ctx, int n,
 
 #undef UPB_SIZE
 #undef UPB_PTR_AT
+#undef UPB_SIZEOF_FLEX
 #undef UPB_MAPTYPE_STRING
 #undef UPB_EXPORT
 #undef UPB_INLINE
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.h b/ruby/ext/google/protobuf_c/ruby-upb.h
index af8d4e30e5..1f6f6a05c7 100755
--- a/ruby/ext/google/protobuf_c/ruby-upb.h
+++ b/ruby/ext/google/protobuf_c/ruby-upb.h
@@ -61,6 +61,15 @@ Error, UINTPTR_MAX is undefined
  */
 #define UPB_PTR_AT(msg, ofs, type) ((type*)((char*)(msg) + (ofs)))
 
+// A flexible array member may have lower alignment requirements than the struct
+// overall - in that case, it can overlap with the trailing padding of the rest
+// of the struct, and a naive sizeof(base) + sizeof(flex) * count calculation
+// will not take into account that overlap, and allocate more than is required.
+#define UPB_SIZEOF_FLEX(type, member, count) \
+  (UPB_MAX(sizeof(type),                     \
+           (offsetof(type, member) +         \
+            count * (offsetof(type, member[1]) - offsetof(type, member[0])))))
+
 #define UPB_MAPTYPE_STRING 0
 
 // UPB_EXPORT: always generate a public symbol.
@@ -15341,6 +15350,7 @@ upb_MethodDef* _upb_MethodDefs_New(upb_DefBuilder* ctx, int n,
 
 #undef UPB_SIZE
 #undef UPB_PTR_AT
+#undef UPB_SIZEOF_FLEX
 #undef UPB_MAPTYPE_STRING
 #undef UPB_EXPORT
 #undef UPB_INLINE