diff --git a/lsp-test.cabal b/lsp-test.cabal
--- a/lsp-test.cabal
+++ b/lsp-test.cabal
@@ -1,5 +1,5 @@
 name:                lsp-test
-version:             0.11.0.4
+version:             0.11.0.5
 synopsis:            Functional test framework for LSP servers.
 description:
   A test framework for writing tests against
diff --git a/src/Language/Haskell/LSP/Test/Decoding.hs b/src/Language/Haskell/LSP/Test/Decoding.hs
--- a/src/Language/Haskell/LSP/Test/Decoding.hs
+++ b/src/Language/Haskell/LSP/Test/Decoding.hs
@@ -116,6 +116,7 @@
   TextDocumentDocumentLink      -> RspDocumentLink . decoded
   DocumentLinkResolve           -> RspDocumentLinkResolve . decoded
   TextDocumentWillSaveWaitUntil -> RspWillSaveWaitUntil . decoded
+  CustomClientMethod{}          -> RspCustomServer . decoded
   x                             -> error . ((show x ++ " is not a request: ") ++) . show
   where decoded x = fromMaybe (error $ "Couldn't decode response for the request type: "
                                         ++ show req ++ "\n" ++ show x)