diff --git a/Handler/ListChallenges.hs b/Handler/ListChallenges.hs
index b93f6da..d584e7c 100644
--- a/Handler/ListChallenges.hs
+++ b/Handler/ListChallenges.hs
@@ -101,7 +101,7 @@ declareVersionInfoSwagger = do
 
   return $ mempty
     & paths .~
-        [ ("/api/version-info/{challengeName}",
+        [ ("/api/version-info/{versionHash}",
             mempty & get ?~ (mempty
                                  & parameters .~ [ Inline $ mempty
                                                    & name .~ "versionHash"
diff --git a/PersistSHA1.hs b/PersistSHA1.hs
index 8cd4740..2eca021 100644
--- a/PersistSHA1.hs
+++ b/PersistSHA1.hs
@@ -55,6 +55,7 @@ hexNibbleToWord8 'E' = 14
 hexNibbleToWord8 'e' = 14
 hexNibbleToWord8 'F' = 15
 hexNibbleToWord8 'f' = 15
+hexNibbleToWord8 c = error ("Unexpected char '" ++ [c] ++ "'")
 
 instance PersistField SHA1 where
   toPersistValue (SHA1 t) = PersistByteString t