diff --git a/action_processor.h b/action_processor.h
index 124fe00..ef06181 100644
--- a/action_processor.h
+++ b/action_processor.h
@@ -40,6 +40,7 @@
   kActionCodeDownloadWriteError = 14,
   kActionCodeNewRootfsVerificationError = 15,
   kActionCodeNewKernelVerificationError = 16,
+  kActionCodeSignedDeltaPayloadExpectedError = 17,
   kActionCodeOmahaRequestEmptyResponseError = 200,
   kActionCodeOmahaRequestXMLParseError = 201,
   kActionCodeOmahaRequestNoUpdateCheckNode = 202,