diff --git a/objectivec/GPBDescriptor_PackagePrivate.h b/objectivec/GPBDescriptor_PackagePrivate.h
index 7065164a33126..cc437c40a90e1 100644
--- a/objectivec/GPBDescriptor_PackagePrivate.h
+++ b/objectivec/GPBDescriptor_PackagePrivate.h
@@ -89,13 +89,8 @@ typedef struct GPBMessageFieldDescription {
   // C identifier for large apps.
   const char *name;
   union {
-    // className is deprecated and will be removed in favor of clazz.
-    // kept around right now for backwards compatibility.
-    // clazz is used iff GPBDescriptorInitializationFlag_UsesClassRefs is set.
-    char *className;  // Name of the class of the message.
-    Class clazz;      // Class of the message.
-    // For enums only.
-    GPBEnumDescriptorFunc enumDescFunc;
+    Class clazz;                         // Class of the message.
+    GPBEnumDescriptorFunc enumDescFunc;  // Function to get the enum descriptor.
   } dataTypeSpecific;
   // The field number for the ivar.
   uint32_t number;
@@ -134,29 +129,12 @@ typedef NS_OPTIONS(uint8_t, GPBExtensionOptions) {
 typedef struct GPBExtensionDescription {
   GPBGenericValue defaultValue;
   const char *singletonName;
-  // Before 3.12, `extendedClass` was just a `const char *`. Thanks to nested
-  // initialization
-  // (https://en.cppreference.com/w/c/language/struct_initialization#Nested_initialization) old
-  // generated code with `.extendedClass = GPBStringifySymbol(Something)` still works; and the
-  // current generator can use `extendedClass.clazz`, to pass a Class reference.
   union {
-    const char *name;
     Class clazz;
   } extendedClass;
-  // Before 3.12, this was `const char *messageOrGroupClassName`. In the
-  // initial 3.12 release, we moved the `union messageOrGroupClass`, and failed
-  // to realize that would break existing source code for extensions. So to
-  // keep existing source code working, we added an unnamed union (C11) to
-  // provide both the old field name and the new union. This keeps both older
-  // and newer code working.
-  // Background: https://github.com/protocolbuffers/protobuf/issues/7555
   union {
-    const char *messageOrGroupClassName;
-    union {
-      const char *name;
-      Class clazz;
-    } messageOrGroupClass;
-  };
+    Class clazz;
+  } messageOrGroupClass;
   GPBEnumDescriptorFunc enumDescriptorFunc;
   int32_t fieldNumber;
   GPBDataType dataType;