diff --git a/Network/CryptoConditions/Json.hs b/Network/CryptoConditions/Json.hs
--- a/Network/CryptoConditions/Json.hs
+++ b/Network/CryptoConditions/Json.hs
@@ -15,6 +15,7 @@
   ) where
 
 
+import Control.Monad.Fail (MonadFail)
 import Crypto.PubKey.Ed25519
 import Crypto.Error
 
@@ -95,7 +96,7 @@
 -- Util
 --
 
-fromB64 :: Text -> Parser ByteString
+fromB64 :: MonadFail m => Text -> m ByteString
 fromB64 = either fail pure . b64DecodeStripped . encodeUtf8
 
 
diff --git a/cryptoconditions.cabal b/cryptoconditions.cabal
--- a/cryptoconditions.cabal
+++ b/cryptoconditions.cabal
@@ -1,5 +1,5 @@
 name:                cryptoconditions
-version:             0.2.4
+version:             0.2.5
 synopsis:            Interledger Crypto-Conditions
 description:         Please see README.md
 homepage:            https://github.com/libscott/cryptoconditions-hs