diff --git a/delta_performer.h b/delta_performer.h
index 7943d7a..a9cbe44 100644
--- a/delta_performer.h
+++ b/delta_performer.h
@@ -36,6 +36,7 @@
 
   static const uint64_t kDeltaVersionSize;
   static const uint64_t kDeltaManifestSizeSize;
+  static const uint64_t kSupportedMajorPayloadVersion;
   static const char kUpdatePayloadPublicKeyPath[];
 
   // Defines the granularity of progress logging in terms of how many "completed
@@ -163,15 +164,18 @@
     public_key_path_ = public_key_path;
   }
 
-  // Returns the byte offset at which the manifest protobuf begins in a
-  // payload.
-  static uint64_t GetManifestOffset();
+  // Returns the byte offset at which the payload version can be found.
+  static uint64_t GetVersionOffset();
 
   // Returns the byte offset where the size of the manifest is stored in
   // a payload. This offset precedes the actual start of the manifest
   // that's returned by the GetManifestOffset method.
   static uint64_t GetManifestSizeOffset();
 
+  // Returns the byte offset at which the manifest protobuf begins in a
+  // payload.
+  static uint64_t GetManifestOffset();
+
  private:
   friend class DeltaPerformerTest;
   FRIEND_TEST(DeltaPerformerTest, IsIdempotentOperationTest);