diff --git a/src/Network/Ethereum/Web3/TH.hs b/src/Network/Ethereum/Web3/TH.hs
--- a/src/Network/Ethereum/Web3/TH.hs
+++ b/src/Network/Ethereum/Web3/TH.hs
@@ -238,7 +238,7 @@
         , instanceD' dataName encodingT
             (funEncodigD dataName (length inputs) mIdent)
         , instanceD' dataName methodT [] ]
-  where mIdent    = T.unpack (methodId fun)
+  where mIdent    = T.unpack (methodId $ fun{funName = T.replace "'" "" name})
         dataName  = mkName (toUpperFirst (T.unpack $ name <> "Data"))
         funName   = mkName (toLowerFirst (T.unpack name))
         bangInput = fmap funBangType inputs
diff --git a/web3.cabal b/web3.cabal
--- a/web3.cabal
+++ b/web3.cabal
@@ -1,5 +1,5 @@
 name:                web3
-version:             0.4.0.0
+version:             0.4.1.0
 synopsis:            Ethereum API for Haskell
 description:         Web3 is a Haskell client library for Ethereum
 homepage:            https://github.com/airalab/hs-web3#readme