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 502bf57bd0..468f287a22 100644
--- a/php/ext/google/protobuf/php-upb.c
+++ b/php/ext/google/protobuf/php-upb.c
@@ -3603,13 +3603,19 @@ void upb_Array_Freeze(upb_Array* arr, const upb_MiniTable* m) {
 
 // Must be last.
 
-const upb_MiniTableExtension* upb_Message_ExtensionByIndex(
-    const upb_Message* msg, size_t index) {
+bool upb_Message_NextExtension(const upb_Message* msg,
+                               const upb_MiniTableExtension** result,
+                               uintptr_t* iter) {
   size_t count;
   const upb_Extension* ext = UPB_PRIVATE(_upb_Message_Getexts)(msg, &count);
-
-  UPB_ASSERT(index < count);
-  return ext[index].ext;
+  size_t i = *iter;
+  if (i >= count) {
+    return false;
+    *result = NULL;
+  }
+  *result = ext[i].ext;
+  *iter = i + 1;
+  return true;
 }
 
 const upb_MiniTableExtension* upb_Message_FindExtensionByNumber(
diff --git a/php/ext/google/protobuf/php-upb.h b/php/ext/google/protobuf/php-upb.h
index 2aca71f940..e87af89fe9 100644
--- a/php/ext/google/protobuf/php-upb.h
+++ b/php/ext/google/protobuf/php-upb.h
@@ -13571,9 +13571,11 @@ UPB_INLINE bool _upb_NonAtomic_CompareExchangeStrongP(void* addr,
 extern "C" {
 #endif
 
-const upb_MiniTableExtension* upb_Message_ExtensionByIndex(
-    const upb_Message* msg, size_t index);
+#define kUpb_Message_ExtensionBegin 0;
 
+bool upb_Message_NextExtension(const upb_Message* msg,
+                               const upb_MiniTableExtension** result,
+                               uintptr_t* iter);
 // Returns the minitable with the given field number, or NULL on failure.
 const upb_MiniTableExtension* upb_Message_FindExtensionByNumber(
     const upb_Message* msg, uint32_t field_number);
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.c b/ruby/ext/google/protobuf_c/ruby-upb.c
index 6039bcd55f..e7abb2159f 100644
--- a/ruby/ext/google/protobuf_c/ruby-upb.c
+++ b/ruby/ext/google/protobuf_c/ruby-upb.c
@@ -3603,13 +3603,19 @@ void upb_Array_Freeze(upb_Array* arr, const upb_MiniTable* m) {
 
 // Must be last.
 
-const upb_MiniTableExtension* upb_Message_ExtensionByIndex(
-    const upb_Message* msg, size_t index) {
+bool upb_Message_NextExtension(const upb_Message* msg,
+                               const upb_MiniTableExtension** result,
+                               uintptr_t* iter) {
   size_t count;
   const upb_Extension* ext = UPB_PRIVATE(_upb_Message_Getexts)(msg, &count);
-
-  UPB_ASSERT(index < count);
-  return ext[index].ext;
+  size_t i = *iter;
+  if (i >= count) {
+    return false;
+    *result = NULL;
+  }
+  *result = ext[i].ext;
+  *iter = i + 1;
+  return true;
 }
 
 const upb_MiniTableExtension* upb_Message_FindExtensionByNumber(
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.h b/ruby/ext/google/protobuf_c/ruby-upb.h
index f564c75dcb..2d8853d797 100755
--- a/ruby/ext/google/protobuf_c/ruby-upb.h
+++ b/ruby/ext/google/protobuf_c/ruby-upb.h
@@ -13573,9 +13573,11 @@ UPB_INLINE bool _upb_NonAtomic_CompareExchangeStrongP(void* addr,
 extern "C" {
 #endif
 
-const upb_MiniTableExtension* upb_Message_ExtensionByIndex(
-    const upb_Message* msg, size_t index);
+#define kUpb_Message_ExtensionBegin 0;
 
+bool upb_Message_NextExtension(const upb_Message* msg,
+                               const upb_MiniTableExtension** result,
+                               uintptr_t* iter);
 // Returns the minitable with the given field number, or NULL on failure.
 const upb_MiniTableExtension* upb_Message_FindExtensionByNumber(
     const upb_Message* msg, uint32_t field_number);