some comments from the review

Author: randygrok

test/mocks/Store.go test/mocks/store.gotest/mocks/Store.go renamed to test/mocks/store.go

@@ -22,7 +22,7 @@ func SetHeaderHasher(hasher HeaderHasher) {
 func (h *Header) Hash() Hash {
 	hash, err := DefaultHeaderHasher(h)
 	if err != nil {
-		// For backward compatibility, return nil on error
+		// For backward compatibility with go-header
 		// In the future, this method signature could be changed to return (Hash, error)
 		return nil
 	}

types/hashing.go

@@ -12,7 +12,7 @@ import (
 // The Consensus.App version will be set during the Handshake, once
 // we hear from the app what protocol version it is running.
 var InitStateVersion = Version{
-	Block: 11,
+	Block: 11, // this is needed for IBC compatibility
 	App:   0,
 }