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:             0.5.1.3
+version:             0.5.1.4
 synopsis:            Functional test framework for LSP servers.
 description:
   A test framework for writing tests against
@@ -36,7 +36,7 @@
                      , parser-combinators:Control.Applicative.Combinators
   default-language:    Haskell2010
   build-depends:       base >= 4.10 && < 5
-                     , haskell-lsp >= 0.8 && < 0.11
+                     , haskell-lsp == 0.11.*
                      , aeson
                      , aeson-pretty
                      , ansi-terminal
@@ -78,7 +78,7 @@
   build-depends:       base >= 4.10 && < 5
                      , hspec
                      , lens
-                     , haskell-lsp >= 0.8 && < 0.11
+                     , haskell-lsp == 0.11.*
                      , lsp-test
                      , data-default
                      , aeson
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
@@ -46,7 +46,7 @@
 
 getHeaders :: Handle -> IO [(String, String)]
 getHeaders h = do
-  l <- catch (hGetLine h) eofHandler 
+  l <- catch (hGetLine h) eofHandler
   let (name, val) = span (/= ':') l
   if null val then return [] else ((name, drop 2 val) :) <$> getHeaders h
   where eofHandler e
@@ -134,7 +134,6 @@
         WindowProgressStart            -> NotProgressStart $ fromJust $ decode bytes
         WindowProgressReport           -> NotProgressReport $ fromJust $ decode bytes
         WindowProgressDone             -> NotProgressDone $ fromJust $ decode bytes
-        WindowProgressCancel           -> NotProgressCancel $ fromJust $ decode bytes
         TelemetryEvent                 -> NotTelemetry $ fromJust $ decode bytes
         WindowShowMessageRequest       -> ReqShowMessage $ fromJust $ decode bytes
         ClientRegisterCapability       -> ReqRegisterCapability $ fromJust $ decode bytes
diff --git a/src/Language/Haskell/LSP/Test/Messages.hs b/src/Language/Haskell/LSP/Test/Messages.hs
--- a/src/Language/Haskell/LSP/Test/Messages.hs
+++ b/src/Language/Haskell/LSP/Test/Messages.hs
@@ -93,7 +93,6 @@
     (NotProgressStart            m) -> notification m
     (NotProgressReport           m) -> notification m
     (NotProgressDone             m) -> notification m
-    (NotProgressCancel           m) -> notification m
     (NotTelemetry                m) -> notification m
     (NotCancelRequestFromServer  m) -> notification m
 
@@ -145,4 +144,5 @@
  (NotDidSaveTextDocument      m) -> notification m
  (NotDidChangeWatchedFiles    m) -> notification m
  (NotDidChangeWorkspaceFolders m) -> notification m
+ (NotProgressCancel           m) -> notification m
  (UnknownFromClientMessage    m) -> error $ "Unknown message sent from client: " ++ show m