diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,20 @@
 # Revision history for haskell-lsp
 
+## 0.24.0.0
+
+* Add and 'isPreferred' and 'disabled' fields to CodeAction
+
+## 0.23.0.0
+
+* Add runWith for transporots other than stdio (@paulyoung)
+* Fix race condition in event captures (@bgamari)
+* Tweak the sectionSeparator (@alanz)
+* Add hashWithSaltInstances (@ndmitchell)
+* Fix CompletionItem.tags not being optional (@bubba)
+* Avoid unnecessary normalisation in Binary instance for
+  NormalizedFilePath (@cocreature)
+* Fix ordering of TH splices (@fendor)
+
 ## 0.22.0.0
 
 * ResponseMessage results are now an Either type (@greenhat)
diff --git a/haskell-lsp.cabal b/haskell-lsp.cabal
--- a/haskell-lsp.cabal
+++ b/haskell-lsp.cabal
@@ -1,5 +1,5 @@
 name:                haskell-lsp
-version:             0.22.0.0
+version:             0.24.0.0
 synopsis:            Haskell library for the Microsoft Language Server Protocol
 
 description:         An implementation of the types, and basic message server to
@@ -46,7 +46,7 @@
                      , filepath
                      , hslogger
                      , hashable
-                     , haskell-lsp-types == 0.22.*
+                     , haskell-lsp-types == 0.24.*
                      , lens >= 4.15.2
                      , mtl
                      , network-uri
diff --git a/src/Language/Haskell/LSP/Capture.hs b/src/Language/Haskell/LSP/Capture.hs
--- a/src/Language/Haskell/LSP/Capture.hs
+++ b/src/Language/Haskell/LSP/Capture.hs
@@ -1,30 +1,55 @@
 {-# LANGUAGE DeriveAnyClass #-}
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE OverloadedStrings #-}
-module Language.Haskell.LSP.Capture where
+module Language.Haskell.LSP.Capture
+  ( Event(..)
+  , CaptureContext
+  , noCapture
+  , captureToFile
+  , captureFromClient
+  , captureFromServer
+  ) where
 
 import Data.Aeson
 import Data.ByteString.Lazy.Char8 as BSL
 import Data.Time.Clock
 import GHC.Generics
 import Language.Haskell.LSP.Messages
+import System.IO
+import Language.Haskell.LSP.Utility
+import Control.Concurrent
+import Control.Monad
+import Control.Concurrent.STM
 
-data Event = FromClient UTCTime FromClientMessage
-           | FromServer UTCTime FromServerMessage
+data Event = FromClient !UTCTime !FromClientMessage
+           | FromServer !UTCTime !FromServerMessage
   deriving (Show, Eq, Generic, ToJSON, FromJSON)
 
-captureFromServer :: FromServerMessage -> Maybe FilePath -> IO ()
-captureFromServer _ Nothing = return ()
-captureFromServer msg (Just fp) = do
-  time <- getCurrentTime
-  let entry = FromServer time msg
+data CaptureContext = NoCapture | Capture (TChan Event)
 
-  BSL.appendFile fp $ BSL.append (encode entry) "\n"
+noCapture :: CaptureContext
+noCapture = NoCapture
 
-captureFromClient :: FromClientMessage -> Maybe FilePath -> IO ()
-captureFromClient _ Nothing = return ()
-captureFromClient msg (Just fp) = do
+captureToFile :: FilePath -> IO CaptureContext
+captureToFile fname = do
+    logs $ "haskell-lsp:Logging to " ++ fname
+    chan <- newTChanIO
+    _tid <- forkIO $ withFile fname WriteMode $ writeToHandle chan
+    return $ Capture chan
+
+captureFromServer :: FromServerMessage -> CaptureContext -> IO ()
+captureFromServer _ NoCapture = return ()
+captureFromServer msg (Capture chan) = do
   time <- getCurrentTime
-  let entry = FromClient time msg
+  atomically $ writeTChan chan $ FromServer time msg
 
-  BSL.appendFile fp $ BSL.append (encode entry) "\n"
+captureFromClient :: FromClientMessage -> CaptureContext -> IO ()
+captureFromClient _ NoCapture = return ()
+captureFromClient msg (Capture chan) = do
+  time <- getCurrentTime
+  atomically $ writeTChan chan $ FromClient time msg
+
+writeToHandle :: TChan Event -> Handle -> IO ()
+writeToHandle chan hdl = forever $ do
+    ev <- atomically $ readTChan chan
+    BSL.hPutStrLn hdl $ encode ev
diff --git a/src/Language/Haskell/LSP/Control.hs b/src/Language/Haskell/LSP/Control.hs
--- a/src/Language/Haskell/LSP/Control.hs
+++ b/src/Language/Haskell/LSP/Control.hs
@@ -8,6 +8,7 @@
 module Language.Haskell.LSP.Control
   (
     run
+  , runWith
   , runWithHandles
   ) where
 
@@ -50,8 +51,7 @@
     -> IO Int
 run = runWithHandles stdin stdout
 
--- | Starts listening and sending requests and responses
--- at the specified handles.
+-- | Convenience function for 'runWith' using the specified handles.
 runWithHandles :: (Show config) =>
        Handle
     -- ^ Handle to read client input from.
@@ -63,20 +63,44 @@
     -> Maybe FilePath
     -> IO Int         -- exit code
 runWithHandles hin hout initializeCallbacks h o captureFp = do
-
-  logm $ B.pack "\n\n\n\n\nhaskell-lsp:Starting up server ..."
   hSetBuffering hin NoBuffering
   hSetEncoding  hin utf8
 
   hSetBuffering hout NoBuffering
   hSetEncoding  hout utf8
 
+  let
+    clientIn = BS.hGetSome hin defaultChunkSize
+
+    clientOut out = do
+      BSL.hPut hout out
+      hFlush hout
+
+  runWith clientIn clientOut initializeCallbacks h o captureFp
+
+-- | Starts listening and sending requests and responses
+-- using the specified I/O.
+runWith :: (Show config) =>
+       IO BS.ByteString
+    -- ^ Client input.
+    -> (BSL.ByteString -> IO ())
+    -- ^ Function to provide output to.
+    -> Core.InitializeCallbacks config
+    -> Core.Handlers
+    -> Core.Options
+    -> Maybe FilePath
+    -> IO Int         -- exit code
+runWith clientIn clientOut initializeCallbacks h o captureFp = do
+
+  logm $ B.pack "\n\n\n\n\nhaskell-lsp:Starting up server ..."
+
   timestamp <- formatTime defaultTimeLocale (iso8601DateFormat (Just "%H-%M-%S")) <$> getCurrentTime
   let timestampCaptureFp = fmap (\f -> dropExtension f ++ timestamp ++ takeExtension f)
                                 captureFp
+  captureCtx <- maybe (return noCapture) captureToFile timestampCaptureFp
 
   cout <- atomically newTChan :: IO (TChan FromServerMessage)
-  _rhpid <- forkIO $ sendServer cout hout timestampCaptureFp
+  _rhpid <- forkIO $ sendServer cout clientOut captureCtx
 
 
   let sendFunc :: Core.SendFunc
@@ -85,20 +109,20 @@
 
   tvarId <- atomically $ newTVar 0
   initVFS $ \vfs -> do
-    tvarDat <- atomically $ newTVar $ Core.defaultLanguageContextData h o lf tvarId sendFunc timestampCaptureFp vfs
+    tvarDat <- atomically $ newTVar $ Core.defaultLanguageContextData h o lf tvarId sendFunc captureCtx vfs
 
-    ioLoop hin initializeCallbacks tvarDat
+    ioLoop clientIn initializeCallbacks tvarDat
 
   return 1
 
 
 -- ---------------------------------------------------------------------
 
-ioLoop :: (Show config) => Handle
+ioLoop :: (Show config) => IO BS.ByteString
                    -> Core.InitializeCallbacks config
                    -> TVar (Core.LanguageContextData config)
                    -> IO ()
-ioLoop hin dispatcherProc tvarDat =
+ioLoop clientIn dispatcherProc tvarDat =
   go (parse parser "")
   where
     go :: Result BS.ByteString -> IO ()
@@ -106,7 +130,7 @@
       "\nhaskell-lsp: Failed to parse message header:\n" <> B.intercalate " > " (map str2lbs ctxs) <> ": " <>
       str2lbs err <> "\n exiting 1 ...\n"
     go (Partial c) = do
-      bs <- BS.hGetSome hin defaultChunkSize
+      bs <- clientIn
       if BS.null bs
         then logm $ B.pack "\nhaskell-lsp:Got EOF, exiting 1 ...\n"
         else go (c bs)
@@ -123,8 +147,8 @@
 -- ---------------------------------------------------------------------
 
 -- | Simple server to make sure all output is serialised
-sendServer :: TChan FromServerMessage -> Handle -> Maybe FilePath -> IO ()
-sendServer msgChan clientH captureFp =
+sendServer :: TChan FromServerMessage -> (BSL.ByteString -> IO ()) -> CaptureContext -> IO ()
+sendServer msgChan clientOut captureCtxt =
   forever $ do
     msg <- atomically $ readTChan msgChan
 
@@ -138,11 +162,10 @@
                  , BSL.fromStrict _TWO_CRLF
                  , str ]
 
-    BSL.hPut clientH out
-    hFlush clientH
+    clientOut out
     logm $ B.pack "<--2--" <> str
 
-    captureFromServer msg captureFp
+    captureFromServer msg captureCtxt
 
 -- |
 --
diff --git a/src/Language/Haskell/LSP/Core.hs b/src/Language/Haskell/LSP/Core.hs
--- a/src/Language/Haskell/LSP/Core.hs
+++ b/src/Language/Haskell/LSP/Core.hs
@@ -27,6 +27,7 @@
   , sendErrorLogS
   , sendErrorShowS
   , reverseSortEdit
+  , Priority(..)
   ) where
 
 import           Control.Concurrent.Async
@@ -86,7 +87,7 @@
   , resConfig              :: !(Maybe config)
   , resLspId               :: !(TVar Int)
   , resLspFuncs            :: LspFuncs config -- NOTE: Cannot be strict, lazy initialization
-  , resCaptureFile         :: !(Maybe FilePath)
+  , resCaptureContext      :: !CaptureContext
   , resWorkspaceFolders    :: ![J.WorkspaceFolder]
   , resProgressData        :: !ProgressData
   }
@@ -348,7 +349,7 @@
       ctx <- readTVarIO ctxVar
       -- Capture exit notification
       case J.fromJSON v :: J.Result J.ExitNotification of
-        J.Success n -> captureFromClient (NotExit n) (resCaptureFile ctx)
+        J.Success n -> captureFromClient (NotExit n) (resCaptureContext ctx)
         J.Error _ -> return ()
       logm $ B.pack "haskell-lsp:Got exit, exiting"
       exitSuccess
@@ -417,7 +418,7 @@
 
           ctx <- readTVarIO tvarDat
           let req' = wrapper req
-          captureFromClient req' (resCaptureFile ctx)
+          captureFromClient req' (resCaptureContext ctx)
 
           case mh of
             Just h -> h req
@@ -484,7 +485,7 @@
     J.Success req -> do
       ctx <- readTVarIO tvarDat
 
-      captureFromClient (notification req) (resCaptureFile ctx)
+      captureFromClient (notification req) (resCaptureContext ctx)
 
       case parseConfig req of
         Left err -> do
@@ -605,10 +606,10 @@
 -- |
 --
 --
-defaultLanguageContextData :: Handlers -> Options -> LspFuncs config -> TVar Int -> SendFunc -> Maybe FilePath -> VFS -> LanguageContextData config
-defaultLanguageContextData h o lf tv sf cf vfs =
+defaultLanguageContextData :: Handlers -> Options -> LspFuncs config -> TVar Int -> SendFunc -> CaptureContext -> VFS -> LanguageContextData config
+defaultLanguageContextData h o lf tv sf cc vfs =
   LanguageContextData _INITIAL_RESPONSE_SEQUENCE h o sf (VFSData vfs mempty) mempty
-                      Nothing tv lf cf mempty defaultProgressData
+                      Nothing tv lf cc mempty defaultProgressData
 
 defaultProgressData :: ProgressData
 defaultProgressData = ProgressData 0 Map.empty
diff --git a/test/InitialConfigurationSpec.hs b/test/InitialConfigurationSpec.hs
--- a/test/InitialConfigurationSpec.hs
+++ b/test/InitialConfigurationSpec.hs
@@ -6,6 +6,7 @@
 import           Control.Concurrent.STM
 import           Data.Aeson
 import           Data.Default
+import           Language.Haskell.LSP.Capture
 import           Language.Haskell.LSP.Core
 import           Language.Haskell.LSP.Types
 import           Language.Haskell.LSP.VFS
@@ -40,7 +41,7 @@
                                                         undefined
                                                         tvarLspId
                                                         (const $ return ())
-                                                        Nothing
+                                                        noCapture
                                                         vfs
 
     let putMsg msg =
diff --git a/test/JsonSpec.hs b/test/JsonSpec.hs
--- a/test/JsonSpec.hs
+++ b/test/JsonSpec.hs
@@ -3,6 +3,8 @@
 {-# LANGUAGE OverloadedStrings    #-}
 {-# LANGUAGE TypeSynonymInstances #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
+-- For the use of MarkedString
+{-# OPTIONS_GHC -fno-warn-deprecations #-}
 -- | Test for JSON serialization
 module JsonSpec where
 
@@ -44,6 +46,11 @@
          (propertyJsonRoundtrip :: ResponseMessage () -> Property)
     prop "ResponseMessage JSON value"
          (propertyJsonRoundtrip :: ResponseMessage J.Value -> Property)
+  describe "JSON decoding regressions" $
+    it "CompletionItem" $
+      (J.decode "{\"jsonrpc\":\"2.0\",\"result\":[{\"label\":\"raisebox\"}],\"id\":1}" :: Maybe CompletionResponse)
+        `shouldNotBe` Nothing
+  
 
 responseMessageSpec :: Spec
 responseMessageSpec = do
diff --git a/test/WorkspaceFoldersSpec.hs b/test/WorkspaceFoldersSpec.hs
--- a/test/WorkspaceFoldersSpec.hs
+++ b/test/WorkspaceFoldersSpec.hs
@@ -6,6 +6,7 @@
 import Control.Concurrent.STM
 import Data.Aeson
 import Data.Default
+import Language.Haskell.LSP.Capture
 import Language.Haskell.LSP.Core
 import Language.Haskell.LSP.Types
 import Language.Haskell.LSP.VFS
@@ -31,7 +32,7 @@
                                                         undefined
                                                         tvarLspId
                                                         (const $ return ())
-                                                        Nothing
+                                                        noCapture
                                                         vfs
 
     let putMsg msg =