diff --git a/.stylish-haskell.yaml b/.stylish-haskell.yaml
index 036a8905..887cd8da 100644
--- a/.stylish-haskell.yaml
+++ b/.stylish-haskell.yaml
@@ -191,6 +191,25 @@ steps:
       # Default: false
       space_surround: false
 
+      # Post qualify option moves any qualifies found in import declarations
+      # to the end of the declaration. This also adjust padding for any
+      # unqualified import declarations.
+      #
+      # - true: Qualified as <module name> is moved to the end of the
+      #   declaration.
+      #
+      #   > import Data.Bar
+      #   > import Data.Foo qualified as F
+      #
+      # - false: Qualified remains in the default location and unqualified
+      #   imports are padded to align with qualified imports.
+      #
+      #   > import           Data.Bar
+      #   > import qualified Data.Foo as F
+      #
+      # Default: false
+      post_qualify: true
+
   # Language pragmas
   - language_pragmas:
       # We can generate different styles of language pragma lists.
diff --git a/typed-protocols-cborg/src/Network/TypedProtocol/Codec/CBOR.hs b/typed-protocols-cborg/src/Network/TypedProtocol/Codec/CBOR.hs
index 990960e2..a0ff3a21 100644
--- a/typed-protocols-cborg/src/Network/TypedProtocol/Codec/CBOR.hs
+++ b/typed-protocols-cborg/src/Network/TypedProtocol/Codec/CBOR.hs
@@ -1,11 +1,3 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE LambdaCase          #-}
-{-# LANGUAGE MonoLocalBinds      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.Codec.CBOR
   ( module Network.TypedProtocol.Codec
   , mkCodecCborLazyBS
@@ -16,21 +8,21 @@ module Network.TypedProtocol.Codec.CBOR
   , CBOR.DeserialiseFailure (..)
   ) where
 
-import           Control.Monad.Class.MonadST (MonadST (..))
-import           Control.Monad.ST hiding (stToIO)
-
-import qualified Codec.CBOR.Decoding as CBOR (Decoder)
-import qualified Codec.CBOR.Encoding as CBOR (Encoding)
-import qualified Codec.CBOR.Read as CBOR
-import qualified Codec.CBOR.Write as CBOR
-import qualified Data.ByteString as BS
-import qualified Data.ByteString.Builder as BS
-import qualified Data.ByteString.Builder.Extra as BS
-import qualified Data.ByteString.Lazy as LBS
-import qualified Data.ByteString.Lazy.Internal as LBS (smallChunkSize)
-
-import           Network.TypedProtocol.Codec
-import           Network.TypedProtocol.Core
+import Control.Monad.Class.MonadST (MonadST (..))
+import Control.Monad.ST hiding (stToIO)
+
+import Codec.CBOR.Decoding qualified as CBOR (Decoder)
+import Codec.CBOR.Encoding qualified as CBOR (Encoding)
+import Codec.CBOR.Read qualified as CBOR
+import Codec.CBOR.Write qualified as CBOR
+import Data.ByteString qualified as BS
+import Data.ByteString.Builder qualified as BS
+import Data.ByteString.Builder.Extra qualified as BS
+import Data.ByteString.Lazy qualified as LBS
+import Data.ByteString.Lazy.Internal qualified as LBS (smallChunkSize)
+
+import Network.TypedProtocol.Codec
+import Network.TypedProtocol.Core
 
 
 -- | Construct a 'Codec' for a CBOR based serialisation format, using strict
diff --git a/typed-protocols-cborg/typed-protocols-cborg.cabal b/typed-protocols-cborg/typed-protocols-cborg.cabal
index 64ea2698..01e70df9 100644
--- a/typed-protocols-cborg/typed-protocols-cborg.cabal
+++ b/typed-protocols-cborg/typed-protocols-cborg.cabal
@@ -23,11 +23,11 @@ library
                      cborg            >=0.2.1 && <0.3,
                      singletons,        
 
-                     io-classes:io-classes ^>=1.7,
+                     io-classes      ^>=1.7,
                      typed-protocols ^>=0.4
-
   hs-source-dirs:    src
-  default-language:  Haskell2010
+  default-language:  GHC2021
+  default-extensions: LambdaCase
   ghc-options:       -Wall
                      -Wno-unticked-promoted-constructors
                      -Wcompat
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/Channel.hs b/typed-protocols-examples/src/Network/TypedProtocol/Channel.hs
index 3333928a..0013c95f 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/Channel.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/Channel.hs
@@ -1,9 +1,4 @@
-{-# LANGUAGE CPP                 #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE NamedFieldPuns      #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeApplications    #-}
+{-# LANGUAGE CPP #-}
 
 module Network.TypedProtocol.Channel
   ( Channel (..)
@@ -24,15 +19,15 @@ module Network.TypedProtocol.Channel
   , loggingChannel
   ) where
 
-import           Control.Concurrent.Class.MonadSTM
-import           Control.Monad ((>=>))
-import           Control.Monad.Class.MonadSay
-import           Control.Monad.Class.MonadTimer.SI
-import qualified Data.ByteString as BS
-import qualified Data.ByteString.Lazy as LBS
-import           Data.ByteString.Lazy.Internal (smallChunkSize)
-import           Data.Proxy
-import           Numeric.Natural
+import Control.Concurrent.Class.MonadSTM
+import Control.Monad ((>=>))
+import Control.Monad.Class.MonadSay
+import Control.Monad.Class.MonadTimer.SI
+import Data.ByteString qualified as BS
+import Data.ByteString.Lazy qualified as LBS
+import Data.ByteString.Lazy.Internal (smallChunkSize)
+import Data.Proxy
+import Numeric.Natural
 
 #if !defined(mingw32_HOST_OS)
 import           Network.Socket (Socket)
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/Driver/Simple.hs b/typed-protocols-examples/src/Network/TypedProtocol/Driver/Simple.hs
index 04a4dcfe..93e18233 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/Driver/Simple.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/Driver/Simple.hs
@@ -1,11 +1,3 @@
-{-# LANGUAGE BangPatterns         #-}
-{-# LANGUAGE DataKinds            #-}
-{-# LANGUAGE FlexibleContexts     #-}
-{-# LANGUAGE GADTs                #-}
-{-# LANGUAGE NamedFieldPuns       #-}
-{-# LANGUAGE PolyKinds            #-}
-{-# LANGUAGE RankNTypes           #-}
-{-# LANGUAGE ScopedTypeVariables  #-}
 {-# LANGUAGE TypeFamilies         #-}
 -- @UndecidableInstances@ extensions is required for defining @Show@ instance
 -- of @'TraceSendRecv'@.
@@ -32,15 +24,15 @@ module Network.TypedProtocol.Driver.Simple
   , runDecoderWithChannel
   ) where
 
-import           Network.TypedProtocol.Channel
-import           Network.TypedProtocol.Codec
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Driver
-import           Network.TypedProtocol.Peer
+import Network.TypedProtocol.Channel
+import Network.TypedProtocol.Codec
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Driver
+import Network.TypedProtocol.Peer
 
-import           Control.Monad.Class.MonadAsync
-import           Control.Monad.Class.MonadThrow
-import           Control.Tracer (Tracer (..), contramap, traceWith)
+import Control.Monad.Class.MonadAsync
+import Control.Monad.Class.MonadThrow
+import Control.Tracer (Tracer (..), contramap, traceWith)
 
 
 -- $intro
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Client.hs b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Client.hs
index b6398428..2a68b47d 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Client.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Client.hs
@@ -1,9 +1,3 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE KindSignatures      #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeOperators       #-}
-
 module Network.TypedProtocol.PingPong.Client
   ( -- * Normal client
     PingPongClient (..)
@@ -14,9 +8,9 @@ module Network.TypedProtocol.PingPong.Client
   , pingPongClientPeerPipelined
   ) where
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Peer.Client
-import           Network.TypedProtocol.PingPong.Type
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Peer.Client
+import Network.TypedProtocol.PingPong.Type
 
 -- | A ping-pong client, on top of some effect 'm'.
 --
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Codec.hs b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Codec.hs
index f825dae7..405addca 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Codec.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Codec.hs
@@ -1,15 +1,8 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE KindSignatures      #-}
-{-# LANGUAGE NamedFieldPuns      #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.PingPong.Codec where
 
-import           Network.TypedProtocol.Codec
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.PingPong.Type
+import Network.TypedProtocol.Codec
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.PingPong.Type
 
 
 codecPingPong
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Codec/CBOR.hs b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Codec/CBOR.hs
index 0d674a3b..6dd0499b 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Codec/CBOR.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Codec/CBOR.hs
@@ -1,24 +1,17 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE KindSignatures      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.PingPong.Codec.CBOR where
 
-import           Control.Monad.Class.MonadST
+import Control.Monad.Class.MonadST
 
-import           Data.ByteString.Lazy (ByteString)
+import Data.ByteString.Lazy (ByteString)
 
-import qualified Codec.CBOR.Decoding as CBOR (Decoder, decodeWord)
-import qualified Codec.CBOR.Encoding as CBOR (Encoding, encodeWord)
-import qualified Codec.CBOR.Read as CBOR
+import Codec.CBOR.Decoding qualified as CBOR (Decoder, decodeWord)
+import Codec.CBOR.Encoding qualified as CBOR (Encoding, encodeWord)
+import Codec.CBOR.Read qualified as CBOR
 
-import           Network.TypedProtocol.Codec
-import           Network.TypedProtocol.Codec.CBOR
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.PingPong.Type
+import Network.TypedProtocol.Codec
+import Network.TypedProtocol.Codec.CBOR
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.PingPong.Type
 
 codecPingPong
   :: forall m.
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Examples.hs b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Examples.hs
index efcc6ea8..2aa2bf12 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Examples.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Examples.hs
@@ -1,16 +1,9 @@
-{-# LANGUAGE BangPatterns        #-}
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeOperators       #-}
-
 module Network.TypedProtocol.PingPong.Examples where
 
-import           Network.TypedProtocol.PingPong.Client
-import           Network.TypedProtocol.PingPong.Server
+import Network.TypedProtocol.PingPong.Client
+import Network.TypedProtocol.PingPong.Server
 
-import           Network.TypedProtocol.Peer.Client
+import Network.TypedProtocol.Peer.Client
 
 
 -- | The standard stateless ping-pong server instance.
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Server.hs b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Server.hs
index 768b9621..58696293 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Server.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Server.hs
@@ -1,12 +1,10 @@
-{-# LANGUAGE DataKinds       #-}
-{-# LANGUAGE GADTs           #-}
 {-# LANGUAGE RecordWildCards #-}
 
 module Network.TypedProtocol.PingPong.Server where
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Peer.Server
-import           Network.TypedProtocol.PingPong.Type
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Peer.Server
+import Network.TypedProtocol.PingPong.Type
 
 
 data PingPongServer m a = PingPongServer {
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Type.hs b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Type.hs
index 5c8c5534..a606dcb0 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Type.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/PingPong/Type.hs
@@ -1,14 +1,8 @@
-{-# LANGUAGE DataKinds          #-}
-{-# LANGUAGE EmptyCase          #-}
-{-# LANGUAGE FlexibleInstances  #-}
-{-# LANGUAGE GADTs              #-}
-{-# LANGUAGE StandaloneDeriving #-}
-{-# LANGUAGE TypeFamilies       #-}
-
+{-# LANGUAGE TypeFamilies #-}
 
 module Network.TypedProtocol.PingPong.Type where
 
-import           Network.TypedProtocol.Core
+import Network.TypedProtocol.Core
 
 
 -- | The ping\/pong protocol and the states in its protocol state machine.
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Client.hs b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Client.hs
index 4bb1e6a4..81d93075 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Client.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Client.hs
@@ -1,9 +1,3 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.ReqResp.Client
   ( -- * Normal client
     ReqRespClient (..)
@@ -17,11 +11,11 @@ module Network.TypedProtocol.ReqResp.Client
   , requestOnce
   ) where
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Peer.Client
-import           Network.TypedProtocol.Peer.Server (Server)
-import           Network.TypedProtocol.Proofs (connect)
-import           Network.TypedProtocol.ReqResp.Type
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Peer.Client
+import Network.TypedProtocol.Peer.Server (Server)
+import Network.TypedProtocol.Proofs (connect)
+import Network.TypedProtocol.ReqResp.Type
 
 data ReqRespClient req resp m a where
   SendMsgReq     :: req
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Codec.hs b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Codec.hs
index 9152de55..ae614278 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Codec.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Codec.hs
@@ -1,18 +1,10 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE KindSignatures      #-}
-{-# LANGUAGE NamedFieldPuns      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.ReqResp.Codec where
 
-import           Network.TypedProtocol.Codec
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.PingPong.Codec (decodeTerminatedFrame)
-import           Network.TypedProtocol.ReqResp.Type
-import           Text.Read (readMaybe)
+import Network.TypedProtocol.Codec
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.PingPong.Codec (decodeTerminatedFrame)
+import Network.TypedProtocol.ReqResp.Type
+import Text.Read (readMaybe)
 
 
 codecReqResp ::
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Codec/CBOR.hs b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Codec/CBOR.hs
index 0f12bb3b..18935eee 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Codec/CBOR.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Codec/CBOR.hs
@@ -1,28 +1,21 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE KindSignatures      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.ReqResp.Codec.CBOR where
 
-import           Control.Monad.Class.MonadST
+import Control.Monad.Class.MonadST
 
-import           Data.ByteString.Lazy (ByteString)
+import Data.ByteString.Lazy (ByteString)
 
-import qualified Codec.CBOR.Decoding as CBOR (Decoder, decodeListLen,
-                     decodeWord)
-import qualified Codec.CBOR.Encoding as CBOR (Encoding, encodeListLen,
-                     encodeWord)
-import qualified Codec.CBOR.Read as CBOR
-import           Codec.Serialise.Class (Serialise)
-import qualified Codec.Serialise.Class as CBOR
+import Codec.CBOR.Decoding qualified as CBOR (Decoder, decodeListLen,
+           decodeWord)
+import Codec.CBOR.Encoding qualified as CBOR (Encoding, encodeListLen,
+           encodeWord)
+import Codec.CBOR.Read qualified as CBOR
+import Codec.Serialise.Class (Serialise)
+import Codec.Serialise.Class qualified as CBOR
 
-import           Network.TypedProtocol.Codec
-import           Network.TypedProtocol.Codec.CBOR
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.ReqResp.Type
+import Network.TypedProtocol.Codec
+import Network.TypedProtocol.Codec.CBOR
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.ReqResp.Type
 
 codecReqResp
   :: forall req resp m.
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Examples.hs b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Examples.hs
index ecfb1932..2b7706ac 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Examples.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Examples.hs
@@ -1,15 +1,9 @@
-{-# LANGUAGE BangPatterns        #-}
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.ReqResp.Examples where
 
-import           Network.TypedProtocol.ReqResp.Client
-import           Network.TypedProtocol.ReqResp.Server
+import Network.TypedProtocol.ReqResp.Client
+import Network.TypedProtocol.ReqResp.Server
 
-import           Network.TypedProtocol.Peer.Client
+import Network.TypedProtocol.Peer.Client
 
 -- | An example request\/response client which ignores received responses.
 --
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Server.hs b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Server.hs
index dcb91806..1d8127c1 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Server.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Server.hs
@@ -4,9 +4,9 @@
 
 module Network.TypedProtocol.ReqResp.Server where
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Peer.Server
-import           Network.TypedProtocol.ReqResp.Type
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Peer.Server
+import Network.TypedProtocol.ReqResp.Type
 
 
 data ReqRespServer req resp m a = ReqRespServer {
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Type.hs b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Type.hs
index bd41a9f5..69df3221 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Type.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp/Type.hs
@@ -1,15 +1,8 @@
-{-# LANGUAGE DataKinds          #-}
-{-# LANGUAGE EmptyCase          #-}
-{-# LANGUAGE FlexibleInstances  #-}
-{-# LANGUAGE GADTs              #-}
-{-# LANGUAGE PolyKinds          #-}
-{-# LANGUAGE StandaloneDeriving #-}
-{-# LANGUAGE TypeFamilies       #-}
-
+{-# LANGUAGE TypeFamilies #-}
 
 module Network.TypedProtocol.ReqResp.Type where
 
-import           Network.TypedProtocol.Core
+import Network.TypedProtocol.Core
 
 
 data ReqResp req resp where
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp2/Client.hs b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp2/Client.hs
index aa2fd081..ff6beb8a 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp2/Client.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp2/Client.hs
@@ -1,18 +1,9 @@
-{-# LANGUAGE BangPatterns        #-}
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeApplications    #-}
-
-
-
 module Network.TypedProtocol.ReqResp2.Client where
 
-import           Network.TypedProtocol.ReqResp2.Type
+import Network.TypedProtocol.ReqResp2.Type
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Peer.Client
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Peer.Client
 
 
 reqResp2Client :: forall req resp m.
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp2/Type.hs b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp2/Type.hs
index 14a567b0..706b05ef 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/ReqResp2/Type.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/ReqResp2/Type.hs
@@ -1,15 +1,8 @@
-{-# LANGUAGE DataKinds          #-}
-{-# LANGUAGE EmptyCase          #-}
-{-# LANGUAGE FlexibleInstances  #-}
-{-# LANGUAGE GADTs              #-}
-{-# LANGUAGE PolyKinds          #-}
-{-# LANGUAGE StandaloneDeriving #-}
-{-# LANGUAGE TypeFamilies       #-}
-
+{-# LANGUAGE TypeFamilies #-}
 
 module Network.TypedProtocol.ReqResp2.Type where
 
-import           Network.TypedProtocol.Core
+import Network.TypedProtocol.Core
 
 
 data ReqResp2 req resp where
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Client.hs b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Client.hs
index e72a724b..e5160947 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Client.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Client.hs
@@ -1,18 +1,11 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.Stateful.ReqResp.Client
   ( ReqRespClient (..)
   , reqRespClientPeer
   ) where
 
-import           Data.Typeable
-import           Network.TypedProtocol.Stateful.Peer.Client
-import           Network.TypedProtocol.Stateful.ReqResp.Type
+import Data.Typeable
+import Network.TypedProtocol.Stateful.Peer.Client
+import Network.TypedProtocol.Stateful.ReqResp.Type
 
 data ReqRespClient req m a where
   SendMsgReq  :: Typeable resp
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Codec.hs b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Codec.hs
index 538ffd82..fb1ff8fb 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Codec.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Codec.hs
@@ -1,21 +1,12 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE NamedFieldPuns      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeOperators       #-}
-
 module Network.TypedProtocol.Stateful.ReqResp.Codec where
 
-import           Data.Kind (Type)
-import           Data.Singletons.Decide
-import           Data.Typeable
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.PingPong.Codec (decodeTerminatedFrame)
-import           Network.TypedProtocol.Stateful.Codec
-import           Network.TypedProtocol.Stateful.ReqResp.Type
+import Data.Kind (Type)
+import Data.Singletons.Decide
+import Data.Typeable
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.PingPong.Codec (decodeTerminatedFrame)
+import Network.TypedProtocol.Stateful.Codec
+import Network.TypedProtocol.Stateful.ReqResp.Type
 
 data Some (f :: k -> Type) where
     Some :: Typeable a => f a -> Some f
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Examples.hs b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Examples.hs
index 7827e5a8..817c712e 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Examples.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Examples.hs
@@ -1,14 +1,7 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE NamedFieldPuns      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.Stateful.ReqResp.Examples where
 
-import           Network.TypedProtocol.Stateful.ReqResp.Server
-import           Network.TypedProtocol.Stateful.ReqResp.Type
+import Network.TypedProtocol.Stateful.ReqResp.Server
+import Network.TypedProtocol.Stateful.ReqResp.Type
 
 
 fileRPCServer :: Monad m
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Server.hs b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Server.hs
index 680ad2ea..91a12fa2 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Server.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Server.hs
@@ -1,19 +1,11 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE LambdaCase          #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.Stateful.ReqResp.Server
   ( ReqRespServer (..)
   , reqRespServerPeer
   ) where
 
-import           Data.Typeable
-import           Network.TypedProtocol.Stateful.Peer.Server
-import           Network.TypedProtocol.Stateful.ReqResp.Type
+import Data.Typeable
+import Network.TypedProtocol.Stateful.Peer.Server
+import Network.TypedProtocol.Stateful.ReqResp.Type
 
 
 data ReqRespServer req m a = ReqRespServer {
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Type.hs b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Type.hs
index 31e06339..cb22bfad 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Type.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/Stateful/ReqResp/Type.hs
@@ -1,12 +1,4 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE FlexibleInstances        #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE ScopedTypeVariables      #-}
-{-# LANGUAGE StandaloneDeriving       #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeFamilies             #-}
-
+{-# LANGUAGE TypeFamilies #-}
 
 -- | An RPC protocol which in which request type determines respond time.
 -- Unlike in the `Network.TypedProtocol.ReqResp.Type` where `req` and `resp`
@@ -15,9 +7,9 @@
 --
 module Network.TypedProtocol.Stateful.ReqResp.Type where
 
-import           Data.Kind (Type)
-import           Data.Typeable
-import           Network.TypedProtocol.Core
+import Data.Kind (Type)
+import Data.Typeable
+import Network.TypedProtocol.Core
 
 
 type ReqResp :: (Type -> Type) -> Type
diff --git a/typed-protocols-examples/src/Network/TypedProtocol/Trans/Wedge.hs b/typed-protocols-examples/src/Network/TypedProtocol/Trans/Wedge.hs
index 05a628ad..648964dc 100644
--- a/typed-protocols-examples/src/Network/TypedProtocol/Trans/Wedge.hs
+++ b/typed-protocols-examples/src/Network/TypedProtocol/Trans/Wedge.hs
@@ -1,24 +1,12 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE FlexibleInstances        #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE InstanceSigs             #-}
-{-# LANGUAGE KindSignatures           #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE ScopedTypeVariables      #-}
-{-# LANGUAGE StandaloneDeriving       #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeApplications         #-}
-{-# LANGUAGE TypeFamilies             #-}
-{-# LANGUAGE TypeOperators            #-}
-{-# LANGUAGE UndecidableInstances     #-}
+{-# LANGUAGE TypeFamilies         #-}
+{-# LANGUAGE UndecidableInstances #-}
 
 module Network.TypedProtocol.Trans.Wedge where
 
-import           Network.TypedProtocol.Core
+import Network.TypedProtocol.Core
 
-import qualified Network.TypedProtocol.Peer.Client as Client
-import qualified Network.TypedProtocol.PingPong.Type as PingPong
+import Network.TypedProtocol.Peer.Client qualified as Client
+import Network.TypedProtocol.PingPong.Type qualified as PingPong
 
 
 -- | A [wedge](https://hackage.haskell.org/package/smash-0.1.2/docs/Data-Wedge.html)
diff --git a/typed-protocols-examples/test/Main.hs b/typed-protocols-examples/test/Main.hs
index 950738d6..783f6707 100644
--- a/typed-protocols-examples/test/Main.hs
+++ b/typed-protocols-examples/test/Main.hs
@@ -1,9 +1,9 @@
 module Main (main) where
 
-import           Test.Tasty
+import Test.Tasty
 
-import qualified Network.TypedProtocol.PingPong.Tests as PingPong
-import qualified Network.TypedProtocol.ReqResp.Tests as ReqResp
+import Network.TypedProtocol.PingPong.Tests qualified as PingPong
+import Network.TypedProtocol.ReqResp.Tests qualified as ReqResp
 
 main :: IO ()
 main = defaultMain tests
diff --git a/typed-protocols-examples/test/Network/TypedProtocol/PingPong/Tests.hs b/typed-protocols-examples/test/Network/TypedProtocol/PingPong/Tests.hs
index 65dfabaf..2a486796 100644
--- a/typed-protocols-examples/test/Network/TypedProtocol/PingPong/Tests.hs
+++ b/typed-protocols-examples/test/Network/TypedProtocol/PingPong/Tests.hs
@@ -1,9 +1,4 @@
-{-# LANGUAGE CPP               #-}
-{-# LANGUAGE DataKinds         #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE GADTs             #-}
-{-# LANGUAGE NamedFieldPuns    #-}
-
+{-# LANGUAGE CPP #-}
 -- orphaned arbitrary instances
 {-# OPTIONS_GHC -Wno-orphans #-}
 
@@ -16,39 +11,39 @@ module Network.TypedProtocol.PingPong.Tests
   ) where
 
 
-import           Network.TypedProtocol.Channel
-import           Network.TypedProtocol.Codec
-import           Network.TypedProtocol.Driver.Simple
-import           Network.TypedProtocol.Proofs
+import Network.TypedProtocol.Channel
+import Network.TypedProtocol.Codec
+import Network.TypedProtocol.Driver.Simple
+import Network.TypedProtocol.Proofs
 
-import           Network.TypedProtocol.PingPong.Client
-import           Network.TypedProtocol.PingPong.Codec
-import qualified Network.TypedProtocol.PingPong.Codec.CBOR as CBOR
-import           Network.TypedProtocol.PingPong.Examples
-import           Network.TypedProtocol.PingPong.Server
-import           Network.TypedProtocol.PingPong.Type
+import Network.TypedProtocol.PingPong.Client
+import Network.TypedProtocol.PingPong.Codec
+import Network.TypedProtocol.PingPong.Codec.CBOR qualified as CBOR
+import Network.TypedProtocol.PingPong.Examples
+import Network.TypedProtocol.PingPong.Server
+import Network.TypedProtocol.PingPong.Type
 
-import           Control.Monad.Class.MonadAsync
-import           Control.Monad.Class.MonadSTM
-import           Control.Monad.Class.MonadThrow
-import           Control.Monad.IOSim (runSimOrThrow)
-import           Control.Monad.ST (runST)
-import           Control.Tracer (nullTracer)
+import Control.Monad.Class.MonadAsync
+import Control.Monad.Class.MonadSTM
+import Control.Monad.Class.MonadThrow
+import Control.Monad.IOSim (runSimOrThrow)
+import Control.Monad.ST (runST)
+import Control.Tracer (nullTracer)
 
-import           Data.Functor.Identity (Identity (..))
-import           Data.List (inits, tails)
+import Data.Functor.Identity (Identity (..))
+import Data.List (inits, tails)
 
-import qualified Data.ByteString.Lazy as LBS
+import Data.ByteString.Lazy qualified as LBS
 #if !defined(mingw32_HOST_OS)
-import qualified Network.Socket as Socket
-import           System.Directory (removeFile)
-import           System.IO
-import qualified System.Posix.Files as Posix
+import Network.Socket qualified as Socket
+import System.Directory (removeFile)
+import System.IO
+import System.Posix.Files qualified as Posix
 #endif
 
-import           Test.QuickCheck
-import           Test.Tasty (TestTree, testGroup)
-import           Test.Tasty.QuickCheck (testProperty)
+import Test.QuickCheck
+import Test.Tasty (TestTree, testGroup)
+import Test.Tasty.QuickCheck (testProperty)
 
 
 --
diff --git a/typed-protocols-examples/test/Network/TypedProtocol/ReqResp/Tests.hs b/typed-protocols-examples/test/Network/TypedProtocol/ReqResp/Tests.hs
index a58c21e0..6826e295 100644
--- a/typed-protocols-examples/test/Network/TypedProtocol/ReqResp/Tests.hs
+++ b/typed-protocols-examples/test/Network/TypedProtocol/ReqResp/Tests.hs
@@ -1,57 +1,48 @@
-{-# LANGUAGE CPP                 #-}
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleInstances   #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE NamedFieldPuns      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TupleSections       #-}
-
+{-# LANGUAGE CPP #-}
 -- orphaned arbitrary instances
 {-# OPTIONS_GHC -Wno-orphans #-}
 
-
 module Network.TypedProtocol.ReqResp.Tests (tests) where
 
-import           Network.TypedProtocol.Channel
-import           Network.TypedProtocol.Codec
-import           Network.TypedProtocol.Driver.Simple
-import           Network.TypedProtocol.Proofs
-
-import           Network.TypedProtocol.ReqResp.Client
-import           Network.TypedProtocol.ReqResp.Codec
-import qualified Network.TypedProtocol.ReqResp.Codec.CBOR as CBOR
-import           Network.TypedProtocol.ReqResp.Examples
-import           Network.TypedProtocol.ReqResp.Server
-import           Network.TypedProtocol.ReqResp.Type
-
-import           Control.Exception (throw)
-import           Control.Monad.Class.MonadAsync
-import           Control.Monad.Class.MonadST
-import           Control.Monad.Class.MonadSTM
-import           Control.Monad.Class.MonadThrow
-import           Control.Monad.Class.MonadTimer.SI
-import           Control.Monad.IOSim
-import           Control.Monad.ST (runST)
-import           Control.Tracer (nullTracer)
-
-import           Data.Functor.Identity (Identity (..))
-import           Data.List (intercalate, mapAccumL)
-import           Data.Tuple (swap)
+import Network.TypedProtocol.Channel
+import Network.TypedProtocol.Codec
+import Network.TypedProtocol.Driver.Simple
+import Network.TypedProtocol.Proofs
+
+import Network.TypedProtocol.ReqResp.Client
+import Network.TypedProtocol.ReqResp.Codec
+import Network.TypedProtocol.ReqResp.Codec.CBOR qualified as CBOR
+import Network.TypedProtocol.ReqResp.Examples
+import Network.TypedProtocol.ReqResp.Server
+import Network.TypedProtocol.ReqResp.Type
+
+import Control.Exception (throw)
+import Control.Monad.Class.MonadAsync
+import Control.Monad.Class.MonadST
+import Control.Monad.Class.MonadSTM
+import Control.Monad.Class.MonadThrow
+import Control.Monad.Class.MonadTimer.SI
+import Control.Monad.IOSim
+import Control.Monad.ST (runST)
+import Control.Tracer (nullTracer)
+
+import Data.Functor.Identity (Identity (..))
+import Data.List (intercalate, mapAccumL)
+import Data.Tuple (swap)
 #if !defined(mingw32_HOST_OS)
-import qualified Network.Socket as Socket
-import           System.Directory (removeFile)
-import           System.IO
-import qualified System.Posix.Files as Posix
+import Network.Socket qualified as Socket
+import System.Directory (removeFile)
+import System.IO
+import System.Posix.Files qualified as Posix
 #endif
 
-import           Network.TypedProtocol.PingPong.Tests (splits2, splits2BS,
-                     splits3, splits3BS)
+import Network.TypedProtocol.PingPong.Tests (splits2, splits2BS, splits3,
+           splits3BS)
 
-import           Test.QuickCheck
-import           Test.Tasty (TestTree, testGroup)
-import           Test.Tasty.QuickCheck (testProperty)
-import           Text.Show.Functions ()
+import Test.QuickCheck
+import Test.Tasty (TestTree, testGroup)
+import Test.Tasty.QuickCheck (testProperty)
+import Text.Show.Functions ()
 
 
 --
diff --git a/typed-protocols-examples/typed-protocols-examples.cabal b/typed-protocols-examples/typed-protocols-examples.cabal
index cc6d8ba7..63adb36f 100644
--- a/typed-protocols-examples/typed-protocols-examples.cabal
+++ b/typed-protocols-examples/typed-protocols-examples.cabal
@@ -45,14 +45,6 @@ library
                    , Network.TypedProtocol.Stateful.ReqResp.Examples
 
                    , Network.TypedProtocol.Trans.Wedge
-  other-extensions:  GADTs
-                   , RankNTypes
-                   , PolyKinds
-                   , DataKinds
-                   , ScopedTypeVariables
-                   , TypeFamilies
-                   , TypeOperators
-                   , BangPatterns
   build-depends:     base,
                      bytestring,
                      cborg,
@@ -64,9 +56,12 @@ library
                      time,
                      typed-protocols ^>= 0.4,
                      typed-protocols-cborg,
-                     typed-protocols-stateful,
+                     typed-protocols-stateful
   hs-source-dirs:    src
-  default-language:  Haskell2010
+  default-language:  GHC2021
+  default-extensions: DataKinds
+                      GADTs
+                      LambdaCase
   -- ghc-9.2 pulls `ghc-heap-9.12` which is not compatible
   if impl(ghc < 9.4)
     build-depends: ghc-heap < 9.12
@@ -102,7 +97,9 @@ test-suite test
                    , network
                    , unix
 
-  default-language:  Haskell2010
+  default-language:  GHC2021
+  default-extensions: DataKinds
+                      GADTs
   ghc-options:       -rtsopts
                      -Wall
                      -Wno-unticked-promoted-constructors
diff --git a/typed-protocols-stateful-cborg/src/Network/TypedProtocol/Stateful/Codec/CBOR.hs b/typed-protocols-stateful-cborg/src/Network/TypedProtocol/Stateful/Codec/CBOR.hs
index 552dc597..a9b0fdf4 100644
--- a/typed-protocols-stateful-cborg/src/Network/TypedProtocol/Stateful/Codec/CBOR.hs
+++ b/typed-protocols-stateful-cborg/src/Network/TypedProtocol/Stateful/Codec/CBOR.hs
@@ -1,10 +1,3 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE MonoLocalBinds      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Network.TypedProtocol.Stateful.Codec.CBOR
   ( module Network.TypedProtocol.Stateful.Codec
   , DeserialiseFailure
diff --git a/typed-protocols-stateful-cborg/typed-protocols-stateful-cborg.cabal b/typed-protocols-stateful-cborg/typed-protocols-stateful-cborg.cabal
index c134068a..1de37540 100644
--- a/typed-protocols-stateful-cborg/typed-protocols-stateful-cborg.cabal
+++ b/typed-protocols-stateful-cborg/typed-protocols-stateful-cborg.cabal
@@ -31,8 +31,7 @@ library
                      typed-protocols-stateful
 
   hs-source-dirs:    src
-  default-language:  Haskell2010
-  default-extensions: ImportQualifiedPost
+  default-language:  GHC2021
   ghc-options:       -Wall
                      -Wno-unticked-promoted-constructors
                      -Wcompat
diff --git a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Codec.hs b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Codec.hs
index 33451ac4..82394a53 100644
--- a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Codec.hs
+++ b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Codec.hs
@@ -1,18 +1,10 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE FlexibleInstances        #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE NamedFieldPuns           #-}
-{-# LANGUAGE PatternSynonyms          #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE QuantifiedConstraints    #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE ScopedTypeVariables      #-}
-{-# LANGUAGE TypeFamilies             #-}
-{-# LANGUAGE ViewPatterns             #-}
+{-# LANGUAGE PatternSynonyms       #-}
+{-# LANGUAGE QuantifiedConstraints #-}
+{-# LANGUAGE TypeFamilies          #-}
+{-# LANGUAGE ViewPatterns          #-}
 -- @UndecidableInstances@ extension is required for defining @Show@ instance of
 -- @'AnyMessage'@ and @'AnyMessage'@.
-{-# LANGUAGE UndecidableInstances     #-}
+{-# LANGUAGE UndecidableInstances  #-}
 {-# OPTIONS_GHC -Wno-dodgy-imports #-}
 
 -- | Stateful codec.  This module is intended to be imported qualified.
diff --git a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Driver.hs b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Driver.hs
index 90bdb64a..0209df08 100644
--- a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Driver.hs
+++ b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Driver.hs
@@ -1,14 +1,3 @@
-{-# LANGUAGE BangPatterns             #-}
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE NamedFieldPuns           #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE ScopedTypeVariables      #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeOperators            #-}
-
 -- | Actions for running 'Peer's with a 'Driver'.  This module should be
 -- imported qualified.
 --
diff --git a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer.hs b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer.hs
index 275ef953..c94d9734 100644
--- a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer.hs
+++ b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer.hs
@@ -1,16 +1,5 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE DeriveFunctor            #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE FlexibleInstances        #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE MultiParamTypeClasses    #-}
-{-# LANGUAGE StandaloneDeriving       #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeOperators            #-}
 -- TODO: the 'Functor' instance of 'Peer' is undecidable
-{-# LANGUAGE UndecidableInstances     #-}
+{-# LANGUAGE UndecidableInstances #-}
 
 -- | Protocol stateful EDSL.
 --
diff --git a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer/Client.hs b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer/Client.hs
index 65eed230..6ea19b69 100644
--- a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer/Client.hs
+++ b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer/Client.hs
@@ -1,11 +1,4 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE PatternSynonyms          #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeOperators            #-}
+{-# LANGUAGE PatternSynonyms #-}
 
 -- | Bidirectional patterns for @'Peer' ps 'AsClient'@.   The advantage of
 -- these patterns is that they automatically provide the 'RelativeAgencyEq'
diff --git a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer/Server.hs b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer/Server.hs
index 6c865539..5bec9ee4 100644
--- a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer/Server.hs
+++ b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Peer/Server.hs
@@ -1,11 +1,4 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE PatternSynonyms          #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeOperators            #-}
+{-# LANGUAGE PatternSynonyms #-}
 
 -- | Bidirectional patterns for @'Peer' ps 'AsServer'@.   The advantage of
 -- these patterns is that they automatically provide the 'RelativeAgencyEq'
diff --git a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Proofs.hs b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Proofs.hs
index af1b3805..eaa9922b 100644
--- a/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Proofs.hs
+++ b/typed-protocols-stateful/src/Network/TypedProtocol/Stateful/Proofs.hs
@@ -1,11 +1,4 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeFamilies        #-}
-
+{-# LANGUAGE TypeFamilies #-}
 
 -- This is already implied by the -Wall in the .cabal file, but lets just be
 -- completely explicit about it too, since we rely on the completeness
diff --git a/typed-protocols-stateful/typed-protocols-stateful.cabal b/typed-protocols-stateful/typed-protocols-stateful.cabal
index bc0f891f..9703e167 100644
--- a/typed-protocols-stateful/typed-protocols-stateful.cabal
+++ b/typed-protocols-stateful/typed-protocols-stateful.cabal
@@ -22,24 +22,15 @@ library
                     , Network.TypedProtocol.Stateful.Driver
                     , Network.TypedProtocol.Stateful.Proofs
                     , Network.TypedProtocol.Stateful.Codec
-
-  other-extensions:   GADTs
-                    , RankNTypes
-                    , PolyKinds
-                    , DataKinds
-                    , ScopedTypeVariables
-                    , TypeFamilies
-                    , TypeOperators
-                    , BangPatterns
-  default-extensions: ImportQualifiedPost
   build-depends:      base,
                       contra-tracer,
                       singletons >= 3.0,
                       io-classes,
                       typed-protocols ^>= 0.4
-
   hs-source-dirs:     src
-  default-language:   Haskell2010
+  default-language:   GHC2021
+  default-extensions: DataKinds
+                      GADTs
   ghc-options:        -Wall
                       -Wno-unticked-promoted-constructors
                       -Wcompat
diff --git a/typed-protocols/src/Network/TypedProtocol.hs b/typed-protocols/src/Network/TypedProtocol.hs
index b79a0aec..5f0d716d 100644
--- a/typed-protocols/src/Network/TypedProtocol.hs
+++ b/typed-protocols/src/Network/TypedProtocol.hs
@@ -16,9 +16,9 @@ module Network.TypedProtocol
   , module Network.TypedProtocol.Driver
   ) where
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Driver
-import           Network.TypedProtocol.Proofs
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Driver
+import Network.TypedProtocol.Proofs
 
 
 -- $intro
diff --git a/typed-protocols/src/Network/TypedProtocol/Codec.hs b/typed-protocols/src/Network/TypedProtocol/Codec.hs
index 5b16e98f..8c259ee5 100644
--- a/typed-protocols/src/Network/TypedProtocol/Codec.hs
+++ b/typed-protocols/src/Network/TypedProtocol/Codec.hs
@@ -1,14 +1,5 @@
-{-# LANGUAGE DataKinds             #-}
-{-# LANGUAGE FlexibleContexts      #-}
-{-# LANGUAGE FlexibleInstances     #-}
-{-# LANGUAGE GADTs                 #-}
-{-# LANGUAGE NamedFieldPuns        #-}
 {-# LANGUAGE PatternSynonyms       #-}
-{-# LANGUAGE PolyKinds             #-}
 {-# LANGUAGE QuantifiedConstraints #-}
-{-# LANGUAGE RankNTypes            #-}
-{-# LANGUAGE ScopedTypeVariables   #-}
-{-# LANGUAGE TypeFamilies          #-}
 -- @UndecidableInstances@ extension is required for defining @Show@ instance of
 -- @'AnyMessage'@ and @'AnyMessage'@.
 {-# LANGUAGE UndecidableInstances  #-}
@@ -57,12 +48,12 @@ module Network.TypedProtocol.Codec
   , SomeState (..)
   ) where
 
-import           Control.Exception (Exception)
-import           Data.Kind (Type)
-import           Data.Monoid (All (..))
+import Control.Exception (Exception)
+import Data.Kind (Type)
+import Data.Monoid (All (..))
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Driver (SomeMessage (..))
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Driver (SomeMessage (..))
 
 
 -- | A codec for a 'Protocol' handles the encoding and decoding of typed
diff --git a/typed-protocols/src/Network/TypedProtocol/Core.hs b/typed-protocols/src/Network/TypedProtocol/Core.hs
index e8314979..3fdbb9b3 100644
--- a/typed-protocols/src/Network/TypedProtocol/Core.hs
+++ b/typed-protocols/src/Network/TypedProtocol/Core.hs
@@ -1,20 +1,7 @@
-{-# LANGUAGE ConstraintKinds          #-}
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE DerivingVia              #-}
-{-# LANGUAGE EmptyCase                #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE FlexibleInstances        #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE MultiParamTypeClasses    #-}
-{-# LANGUAGE PatternSynonyms          #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE ScopedTypeVariables      #-}
-{-# LANGUAGE StandaloneDeriving       #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeFamilyDependencies   #-}
-{-# LANGUAGE TypeOperators            #-}
-{-# LANGUAGE ViewPatterns             #-}
+{-# LANGUAGE DerivingVia     #-}
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE TypeFamilies    #-}
+{-# LANGUAGE ViewPatterns    #-}
 
 {-# OPTIONS_HADDOCK show-extensions #-}
 
@@ -64,10 +51,10 @@ module Network.TypedProtocol.Core
   , unsafeIntToNat
   ) where
 
-import           Data.Kind (Constraint, Type)
-import           Unsafe.Coerce (unsafeCoerce)
+import Data.Kind (Constraint, Type)
+import Unsafe.Coerce (unsafeCoerce)
 
-import           Data.Singletons
+import Data.Singletons
 
 -- $intro
 -- A typed protocol between two peers is defined via a state machine: a
diff --git a/typed-protocols/src/Network/TypedProtocol/Driver.hs b/typed-protocols/src/Network/TypedProtocol/Driver.hs
index b12d66c9..607d641d 100644
--- a/typed-protocols/src/Network/TypedProtocol/Driver.hs
+++ b/typed-protocols/src/Network/TypedProtocol/Driver.hs
@@ -1,13 +1,4 @@
-{-# LANGUAGE BangPatterns        #-}
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE EmptyCase           #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE GADTs               #-}
-{-# LANGUAGE NamedFieldPuns      #-}
-{-# LANGUAGE PolyKinds           #-}
-{-# LANGUAGE RankNTypes          #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeFamilies        #-}
+{-# LANGUAGE TypeFamilies #-}
 
 -- | Actions for running 'Peer's with a 'Driver'
 --
@@ -23,15 +14,15 @@ module Network.TypedProtocol.Driver
   , runPipelinedPeerWithDriver
   ) where
 
-import           Data.Void (Void)
+import Data.Void (Void)
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Peer
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Peer
 
-import           Control.Concurrent.Class.MonadSTM.TQueue
-import           Control.Monad.Class.MonadAsync
-import           Control.Monad.Class.MonadFork
-import           Control.Monad.Class.MonadSTM
+import Control.Concurrent.Class.MonadSTM.TQueue
+import Control.Monad.Class.MonadAsync
+import Control.Monad.Class.MonadFork
+import Control.Monad.Class.MonadSTM
 
 
 -- $intro
diff --git a/typed-protocols/src/Network/TypedProtocol/Lemmas.hs b/typed-protocols/src/Network/TypedProtocol/Lemmas.hs
index 20bc5f0a..3e55771f 100644
--- a/typed-protocols/src/Network/TypedProtocol/Lemmas.hs
+++ b/typed-protocols/src/Network/TypedProtocol/Lemmas.hs
@@ -1,9 +1,4 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE EmptyCase                #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeFamilies             #-}
+{-# LANGUAGE TypeFamilies #-}
 
 {-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
 {-# HLINT ignore "Use camelCase" #-}
@@ -16,8 +11,8 @@
 --
 module Network.TypedProtocol.Lemmas where
 
-import           Data.Kind (Type)
-import           Network.TypedProtocol.Core
+import Data.Kind (Type)
+import Network.TypedProtocol.Core
 
 
 -- $about
diff --git a/typed-protocols/src/Network/TypedProtocol/Peer.hs b/typed-protocols/src/Network/TypedProtocol/Peer.hs
index 1f1097c1..92c2c469 100644
--- a/typed-protocols/src/Network/TypedProtocol/Peer.hs
+++ b/typed-protocols/src/Network/TypedProtocol/Peer.hs
@@ -1,13 +1,4 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE DeriveFunctor            #-}
-{-# LANGUAGE DerivingVia              #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE StandaloneDeriving       #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeOperators            #-}
+{-# LANGUAGE DerivingVia #-}
 
 -- | Protocol EDSL.
 --
@@ -22,9 +13,9 @@ module Network.TypedProtocol.Peer
   , unsafeIntToNat
   ) where
 
-import           Data.Kind (Type)
+import Data.Kind (Type)
 
-import           Network.TypedProtocol.Core as Core
+import Network.TypedProtocol.Core as Core
 
 -- | A description of a peer that engages in a protocol.
 --
diff --git a/typed-protocols/src/Network/TypedProtocol/Peer/Client.hs b/typed-protocols/src/Network/TypedProtocol/Peer/Client.hs
index 60c355c4..c77c15d4 100644
--- a/typed-protocols/src/Network/TypedProtocol/Peer/Client.hs
+++ b/typed-protocols/src/Network/TypedProtocol/Peer/Client.hs
@@ -1,11 +1,4 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE PatternSynonyms          #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeOperators            #-}
+{-# LANGUAGE PatternSynonyms #-}
 
 -- | Bidirectional patterns for @'Peer' ps 'AsClient'@.   The advantage of
 -- these patterns is that they automatically provide the 'ReflRelativeAgency'
@@ -35,11 +28,11 @@ module Network.TypedProtocol.Peer.Client
   , Nat (..)
   ) where
 
-import           Data.Kind (Type)
+import Data.Kind (Type)
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Peer (Peer)
-import qualified Network.TypedProtocol.Peer as TP
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Peer (Peer)
+import Network.TypedProtocol.Peer qualified as TP
 
 
 type Client :: forall ps
diff --git a/typed-protocols/src/Network/TypedProtocol/Peer/Server.hs b/typed-protocols/src/Network/TypedProtocol/Peer/Server.hs
index 025fbf3f..67c45623 100644
--- a/typed-protocols/src/Network/TypedProtocol/Peer/Server.hs
+++ b/typed-protocols/src/Network/TypedProtocol/Peer/Server.hs
@@ -1,11 +1,5 @@
-{-# LANGUAGE DataKinds                #-}
-{-# LANGUAGE FlexibleContexts         #-}
-{-# LANGUAGE GADTs                    #-}
-{-# LANGUAGE PatternSynonyms          #-}
-{-# LANGUAGE PolyKinds                #-}
-{-# LANGUAGE RankNTypes               #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeOperators            #-}
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE TypeOperators   #-}
 
 -- | Bidirectional patterns for @'Peer' ps 'AsServer'@.   The advantage of
 -- these patterns is that they automatically provide the 'ReflRelativeAgency'
@@ -35,11 +29,11 @@ module Network.TypedProtocol.Peer.Server
   , Nat (..)
   ) where
 
-import           Data.Kind (Type)
+import Data.Kind (Type)
 
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Peer (Peer)
-import qualified Network.TypedProtocol.Peer as TP
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Peer (Peer)
+import Network.TypedProtocol.Peer qualified as TP
 
 
 type Server :: forall ps
diff --git a/typed-protocols/src/Network/TypedProtocol/Proofs.hs b/typed-protocols/src/Network/TypedProtocol/Proofs.hs
index 69125573..4f70c86a 100644
--- a/typed-protocols/src/Network/TypedProtocol/Proofs.hs
+++ b/typed-protocols/src/Network/TypedProtocol/Proofs.hs
@@ -1,13 +1,5 @@
-{-# LANGUAGE DataKinds             #-}
-{-# LANGUAGE EmptyCase             #-}
-{-# LANGUAGE FlexibleContexts      #-}
-{-# LANGUAGE GADTs                 #-}
-{-# LANGUAGE PolyKinds             #-}
 {-# LANGUAGE QuantifiedConstraints #-}
-{-# LANGUAGE RankNTypes            #-}
-{-# LANGUAGE ScopedTypeVariables   #-}
 {-# LANGUAGE TypeFamilies          #-}
-{-# LANGUAGE TypeOperators         #-}
 
 -- This is already implied by the -Wall in the .cabal file, but lets just be
 -- completely explicit about it too, since we rely on the completeness
@@ -32,10 +24,10 @@ module Network.TypedProtocol.Proofs
   , pipelineInterleaving
   ) where
 
-import           Data.Singletons
-import           Network.TypedProtocol.Core
-import           Network.TypedProtocol.Lemmas
-import           Network.TypedProtocol.Peer
+import Data.Singletons
+import Network.TypedProtocol.Core
+import Network.TypedProtocol.Lemmas
+import Network.TypedProtocol.Peer
 
 
 -- | The 'connect' function takes two peers that agree on a protocol and runs
diff --git a/typed-protocols/typed-protocols.cabal b/typed-protocols/typed-protocols.cabal
index 5fb28990..96e93408 100644
--- a/typed-protocols/typed-protocols.cabal
+++ b/typed-protocols/typed-protocols.cabal
@@ -25,21 +25,14 @@ library
                    , Network.TypedProtocol.Driver
                    , Network.TypedProtocol.Proofs
   other-modules:     Network.TypedProtocol.Lemmas
-
-  other-extensions:  GADTs
-                   , RankNTypes
-                   , PolyKinds
-                   , DataKinds
-                   , ScopedTypeVariables
-                   , TypeFamilies
-                   , TypeOperators
-                   , BangPatterns
   build-depends:     base,
                      io-classes:io-classes ^>= 1.7,
                      singletons >= 3.0
 
   hs-source-dirs:    src
-  default-language:  Haskell2010
+  default-language:  GHC2021
+  default-extensions: DataKinds
+                      GADTs
   ghc-options:       -Wall
                      -Wno-unticked-promoted-constructors
                      -Wcompat