--- a/protoc-c/c_file.cc
+++ b/protoc-c/c_file.cc
@@ -118,7 +118,9 @@
   std::string filename_identifier = FilenameIdentifier(file_->name());
 
   int min_header_version = 1000000;
-#if GOOGLE_PROTOBUF_VERSION >= 4023000
+#if GOOGLE_PROTOBUF_VERSION >= 5026000
+  if (FileDescriptorLegacy(file_).edition() == Edition::EDITION_PROTO3) {
+#elif GOOGLE_PROTOBUF_VERSION >= 4023000
   if (FileDescriptorLegacy(file_).syntax() == FileDescriptorLegacy::SYNTAX_PROTO3) {
 #else
   if (file_->syntax() == FileDescriptor::SYNTAX_PROTO3) {

--- a/protoc-c/c_helpers.h
+++ b/protoc-c/c_helpers.h
@@ -175,7 +175,9 @@
 // Return the syntax version of the file containing the field.
 // This wrapper is needed to be able to compile against protobuf2.
 inline int FieldSyntax(const FieldDescriptor* field) {
-#if GOOGLE_PROTOBUF_VERSION >= 4023000
+#if GOOGLE_PROTOBUF_VERSION >= 5026000
+  return FileDescriptorLegacy(field->file()).edition() == Edition::EDITION_PROTO3 ? 3 : 2;
+#elif GOOGLE_PROTOBUF_VERSION >= 4023000
   return FileDescriptorLegacy(field->file()).syntax() == FileDescriptorLegacy::SYNTAX_PROTO3 ? 3 : 2;
 #else
   return field->file()->syntax() == FileDescriptor::SYNTAX_PROTO3 ? 3 : 2;