diff --git a/example/app/Main.hs b/example/app/Main.hs
index 5d90df4..ae962e0 100644
--- a/example/app/Main.hs
+++ b/example/app/Main.hs
@@ -1,15 +1,13 @@
-module Main where
+module Main (main) where
 
 import Network.FTP.Client
 import qualified Network.FTP.Client.Conduit as FC
 import Conduit
-import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as C
-import Data.Monoid ((<>))
 
 main :: IO ()
-main = withFTPS "hostname.com" 21 $ \h welcome -> do
-    login h "username" "password"
+main = withFTPS "hostname.com" 21 $ \h _welcome -> do
+    _ <- login h "username" "password"
     runConduitRes
         $ FC.mlsd h "."
         .| mapC (C.pack . (<> "\n") . show)
diff --git a/example/example.cabal b/example/example.cabal
index 809ad46..195d6db 100644
--- a/example/example.cabal
+++ b/example/example.cabal
@@ -19,21 +19,36 @@ source-repository head
   type: git
   location: https://github.com/flipstone/ftp-client
 
+flag ci
+  description: More strict ghc options used for development and ci, not intended for end-use.
+  manual: True
+  default: False
+
 executable example-exe
   main-is: Main.hs
   other-modules:
       Paths_example
   hs-source-dirs:
       app
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base
     , bytestring
     , conduit
-    , containers
     , ftp-client
     , ftp-client-conduit
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -O2 -threaded -rtsopts -with-rtsopts=-N -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe -Wunused-packages
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
+  else
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N
 
 test-suite example-test
   type: exitcode-stdio-1.0
@@ -42,7 +57,18 @@ test-suite example-test
       Paths_example
   hs-source-dirs:
       test
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
+  else
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N
diff --git a/example/package.yaml b/example/package.yaml
index 4bdc1b1..e613db0 100644
--- a/example/package.yaml
+++ b/example/package.yaml
@@ -10,31 +10,114 @@ category:            Web
 
 git: https://github.com/flipstone/ftp-client
 
+flags:
+  ci:
+    description: More strict ghc options used for development and ci, not intended for end-use.
+    manual: true
+    default: false
+
 executables:
   example-exe:
     main: Main.hs
     source-dirs: app
     language: Haskell2010
-    ghc-options:
-      - -threaded
-      - -rtsopts
-      - -with-rtsopts=-N
     dependencies:
       - base
       - ftp-client
       - ftp-client-conduit
       - conduit
       - bytestring
-      - containers
+    when:
+      - condition: flag(ci)
+        then:
+          ghc-options:
+            - -O2
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
+            - -Wall
+            - -Werror
+            - -Wcompat
+            - -Widentities
+            - -Winvalid-haddock
+            - -Wmissing-local-signatures
+            - -Wmissing-export-lists
+            - -Wpartial-fields
+            - -Wmissed-specialisations
+            - -Wno-implicit-prelude
+            - -Wno-safe
+            - -Wno-unsafe
+            - -Wunused-packages
+          when:
+            - condition: impl (ghc < 9.4)
+              ghc-options:
+                - -Wno-unticked-promoted-constructors
+            - condition: impl (ghc >= 9.4)
+              ghc-options:
+                - -Wimplicit-lift
+                - -Woperator-whitespace
+                - -Wredundant-bang-patterns
+                - -Wredundant-strictness-flags
+            - condition: impl (ghc >= 9.8)
+              ghc-options:
+                - -Wincomplete-export-warnings
+                - -Wmissing-poly-kind-signatures
+                - -Wterm-variable-capture
+            - condition: impl (ghc >= 9.10)
+              ghc-options:
+                - -Wdefaulted-exception-context
+        else:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
 
 tests:
   example-test:
     main: Spec.hs
     source-dirs: test
     language: Haskell2010
-    ghc-options:
-      - -threaded
-      - -rtsopts
-      - -with-rtsopts=-N
     dependencies:
       - base
+    when:
+      - condition: flag(ci)
+        then:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
+            - -Wall
+            - -Werror
+            - -Wcompat
+            - -Widentities
+            - -Winvalid-haddock
+            - -Wmissing-local-signatures
+            - -Wmissing-export-lists
+            - -Wpartial-fields
+            - -Wmissed-specialisations
+            - -Wno-implicit-prelude
+            - -Wno-safe
+            - -Wno-unsafe
+          when:
+            - condition: impl (ghc < 9.4)
+              ghc-options:
+                - -Wno-unticked-promoted-constructors
+            - condition: impl (ghc >= 9.4)
+              ghc-options:
+                - -Wimplicit-lift
+                - -Woperator-whitespace
+                - -Wredundant-bang-patterns
+                - -Wredundant-strictness-flags
+            - condition: impl (ghc >= 9.8)
+              ghc-options:
+                - -Wincomplete-export-warnings
+                - -Wmissing-poly-kind-signatures
+                - -Wterm-variable-capture
+            - condition: impl (ghc >= 9.10)
+              ghc-options:
+                - -Wdefaulted-exception-context
+        else:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
diff --git a/example/test/Spec.hs b/example/test/Spec.hs
index cd4753f..356ebe8 100644
--- a/example/test/Spec.hs
+++ b/example/test/Spec.hs
@@ -1,2 +1,4 @@
+module Main (main) where
+
 main :: IO ()
 main = putStrLn "Test suite not yet implemented"
diff --git a/ftp-client-conduit/CHANGELOG.md b/ftp-client-conduit/CHANGELOG.md
index c63620f..7b2df8c 100644
--- a/ftp-client-conduit/CHANGELOG.md
+++ b/ftp-client-conduit/CHANGELOG.md
@@ -1,5 +1,20 @@
 # Changelog for ftp-client-conduit
 
+## 0.5.0.7
+
+* Add the missing upper bounds on `bytestring`, `conduit` and `exceptions`.
+
+* Replace conduit's deprecated `Producer` and `Consumer` synonyms with
+  `ConduitT` in the exported signatures of `nlst`, `retr`, `list`, `stor` and
+  `mlsd`. The type variables are left free, so the exported types are unchanged
+  -- `Producer m o` is `forall i. ConduitT i o m ()`, not `ConduitT () o m ()`.
+
+* Raise the `conduit` lower bound to `>= 1.3`. `ConduitT` arrived in conduit
+  1.3, so the previous `>= 1.1` allowed dependency selections that cannot
+  compile the signatures above. The bounds audit only added the missing upper
+  halves; this is the lower half that replacing `Producer` and `Consumer`
+  invalidated.
+
 ## 0.5.0.6
 
 * Correct the `resourcet` bound. `>= 1.2 && < 1.3` excluded `resourcet-1.3.0`,
diff --git a/ftp-client-conduit/ftp-client-conduit.cabal b/ftp-client-conduit/ftp-client-conduit.cabal
index dba243a..37197e0 100644
--- a/ftp-client-conduit/ftp-client-conduit.cabal
+++ b/ftp-client-conduit/ftp-client-conduit.cabal
@@ -5,7 +5,7 @@ cabal-version: 1.12
 -- see: https://github.com/sol/hpack
 
 name:           ftp-client-conduit
-version:        0.5.0.6
+version:        0.5.0.7
 synopsis:       Transfer file with FTP and FTPS with Conduit
 description:    ftp-client is a library for communicating with an FTP server. It works over both a clear channel or TLS. ftp-client-conduit uses conduit to stream files and data in constant space.
 category:       Web
@@ -30,6 +30,11 @@ source-repository head
   type: git
   location: https://github.com/flipstone/ftp-client
 
+flag ci
+  description: More strict ghc options used for development and ci, not intended for end-use.
+  manual: True
+  default: False
+
 library
   exposed-modules:
       Network.FTP.Client.Conduit
@@ -38,17 +43,26 @@ library
   hs-source-dirs:
       src
   default-extensions:
-      RankNTypes
       OverloadedStrings
   build-depends:
       base >=4.16 && <5
-    , bytestring
-    , conduit >=1.1
+    , bytestring >=0.10.8.2 && <0.13
+    , conduit ==1.3.*
     , crypton-connection >=0.3 && <0.5
-    , exceptions
+    , exceptions >=0.10.3 && <0.11
     , ftp-client ==0.5.*
     , resourcet >=1.2 && <1.4
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -O2 -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe -Wunused-packages
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
 
 test-suite ftp-conduit-test
   type: exitcode-stdio-1.0
@@ -57,8 +71,19 @@ test-suite ftp-conduit-test
       Paths_ftp_client_conduit
   hs-source-dirs:
       test
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base >=4.16 && <5
     , ftp-client-conduit
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
+  else
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N
diff --git a/ftp-client-conduit/package.yaml b/ftp-client-conduit/package.yaml
index df43bbb..ec1f36c 100644
--- a/ftp-client-conduit/package.yaml
+++ b/ftp-client-conduit/package.yaml
@@ -1,5 +1,5 @@
 name:                ftp-client-conduit
-version:             0.5.0.6
+version:             0.5.0.7
 synopsis:            Transfer file with FTP and FTPS with Conduit
 description:         ftp-client is a library for communicating with an FTP server. It works over both a clear channel or TLS. ftp-client-conduit uses conduit to stream files and data in constant space.
 homepage:            https://github.com/flipstone/ftp-client
@@ -23,32 +23,113 @@ extra-source-files:
 
 git: https://github.com/flipstone/ftp-client
 
+flags:
+  ci:
+    description: More strict ghc options used for development and ci, not intended for end-use.
+    manual: true
+    default: false
+
 library:
   source-dirs: src
   exposed-modules:
     - Network.FTP.Client.Conduit
   language: Haskell2010
   default-extensions:
-    - RankNTypes
     - OverloadedStrings
   dependencies:
     - base >= 4.16 && < 5
     - ftp-client == 0.5.*
-    - conduit >= 1.1
-    - bytestring
+    - conduit >= 1.3 && < 1.4
+    - bytestring >= 0.10.8.2 && < 0.13
     - resourcet >= 1.2 && < 1.4
     - crypton-connection >= 0.3 && < 0.5
-    - exceptions
+    - exceptions >= 0.10.3 && < 0.11
+  when:
+    - condition: flag(ci)
+      ghc-options:
+        - -O2
+        - -Wall
+        - -Werror
+        - -Wcompat
+        - -Widentities
+        - -Winvalid-haddock
+        - -Wmissing-local-signatures
+        - -Wmissing-export-lists
+        - -Wpartial-fields
+        - -Wmissed-specialisations
+        - -Wno-implicit-prelude
+        - -Wno-safe
+        - -Wno-unsafe
+        - -Wunused-packages
+      when:
+        # Previously the guidance was to always use ticked constructors for type
+        # constructors, but that guidance has been reversed, so we turn the
+        # warning off in older compilers.
+        - condition: impl (ghc < 9.4)
+          ghc-options:
+            - -Wno-unticked-promoted-constructors
+        - condition: impl (ghc >= 9.4)
+          ghc-options:
+            - -Wimplicit-lift
+            - -Woperator-whitespace
+            - -Wredundant-bang-patterns
+            - -Wredundant-strictness-flags
+        - condition: impl (ghc >= 9.8)
+          ghc-options:
+            - -Wincomplete-export-warnings
+            - -Wmissing-poly-kind-signatures
+            - -Wterm-variable-capture
+        - condition: impl (ghc >= 9.10)
+          ghc-options:
+            - -Wdefaulted-exception-context
 
 tests:
   ftp-conduit-test:
     main: Spec.hs
     source-dirs: test
     language: Haskell2010
-    ghc-options:
-      - -threaded
-      - -rtsopts
-      - -with-rtsopts=-N
     dependencies:
       - base >= 4.16 && < 5
       - ftp-client-conduit
+    when:
+      - condition: flag(ci)
+        then:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
+            - -Wall
+            - -Werror
+            - -Wcompat
+            - -Widentities
+            - -Winvalid-haddock
+            - -Wmissing-local-signatures
+            - -Wmissing-export-lists
+            - -Wpartial-fields
+            - -Wmissed-specialisations
+            - -Wno-implicit-prelude
+            - -Wno-safe
+            - -Wno-unsafe
+          when:
+            - condition: impl (ghc < 9.4)
+              ghc-options:
+                - -Wno-unticked-promoted-constructors
+            - condition: impl (ghc >= 9.4)
+              ghc-options:
+                - -Wimplicit-lift
+                - -Woperator-whitespace
+                - -Wredundant-bang-patterns
+                - -Wredundant-strictness-flags
+            - condition: impl (ghc >= 9.8)
+              ghc-options:
+                - -Wincomplete-export-warnings
+                - -Wmissing-poly-kind-signatures
+                - -Wterm-variable-capture
+            - condition: impl (ghc >= 9.10)
+              ghc-options:
+                - -Wdefaulted-exception-context
+        else:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
diff --git a/ftp-client-conduit/src/Network/FTP/Client/Conduit.hs b/ftp-client-conduit/src/Network/FTP/Client/Conduit.hs
index 39955fd..8b9dc17 100644
--- a/ftp-client-conduit/src/Network/FTP/Client/Conduit.hs
+++ b/ftp-client-conduit/src/Network/FTP/Client/Conduit.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE ScopedTypeVariables #-}
+
 {-|
 Module      : Network.FTP.Client
 Description : Transfer files over FTP and FTPS with Conduit
@@ -14,23 +16,21 @@ module Network.FTP.Client.Conduit (
     mlsd
 ) where
 
-import Conduit
-import Control.Monad.IO.Class
+-- MonadResource appears in this module's exported signatures, so it is taken
+-- from resourcet directly rather than through Conduit's re-export. That keeps
+-- the resourcet dependency honest instead of implicit.
+import Conduit hiding (MonadResource)
+import Control.Monad.Trans.Resource (MonadResource)
 import Data.ByteString.Lazy.Internal (defaultChunkSize)
 import System.IO
 import Network.FTP.Client
-    ( sendCommand
-    , sendCommandS
-    , sendAll
-    , sendAllS
+    ( sendCommandS
     , FTPCommand(..)
     , RTypeCode(..)
-    , getLineResp
     , createSendDataCommand
     , createTLSSendDataCommand
     , PortActivity(..)
     , getResponse
-    , getResponseS
     , sIOHandleImpl
     , tlsHandleImpl
     , Security(..)
@@ -40,9 +40,6 @@ import Network.FTP.Client
 import qualified Network.FTP.Client as FTP
 import qualified Data.ByteString as B
 import Data.ByteString (ByteString)
-import Control.Monad.Trans.Resource
-import Data.Monoid ((<>))
-import System.IO.Error
 import Network.Connection
 import qualified Control.Monad.Catch as M
 
@@ -50,17 +47,21 @@ debugging :: Bool
 debugging = False
 
 debugPrint :: (Show a, MonadIO m) => a -> m ()
-debugPrint s = debugPrint' s debugging
-    where
-        debugPrint' _ False = return ()
-        debugPrint' s True = liftIO $ print s
+debugPrint s =
+    if debugging
+        then liftIO $ print s
+        else return ()
 
 debugResponse :: (Show a, MonadIO m) => a -> m ()
 debugResponse s = debugPrint $ "Recieved: " <> (show s)
 
-getAllLineRespC :: MonadIO m => FTP.Handle -> Producer m ByteString
-getAllLineRespC h = loop
-    where
+getAllLineRespC
+    :: forall i m
+     . MonadIO m
+    => FTP.Handle
+    -> ConduitT i ByteString m ()
+getAllLineRespC h =
+    let loop :: ConduitT i ByteString m ()
         loop = do
             line <- liftIO
                 $ FTP.getLineResp h `M.catchIOError` const (return "")
@@ -69,10 +70,15 @@ getAllLineRespC h = loop
                 else do
                     yield line
                     loop
+    in loop
 
-sendAllLineC :: MonadIO m => FTP.Handle -> Consumer ByteString m ()
-sendAllLineC h = loop
-    where
+sendAllLineC
+    :: forall o m
+     . MonadIO m
+    => FTP.Handle
+    -> ConduitT ByteString o m ()
+sendAllLineC h =
+    let loop :: ConduitT ByteString o m ()
         loop = do
             mx <- await
             case mx of
@@ -80,6 +86,7 @@ sendAllLineC h = loop
                 Just x -> do
                     liftIO $ FTP.sendLine h x
                     loop
+    in loop
 
 sourceDataCommandSecurity
     :: MonadResource m
@@ -103,7 +110,7 @@ sourceDataCommand
     -> (FTP.Handle -> ConduitM i o m r)
     -> ConduitM i o m r
 sourceDataCommand ch pa code cmd f = do
-    sendCommandS ch $ RType code
+    _ <- sendCommandS ch $ RType code
     x <- bracketP
         (createSendDataCommand ch pa cmd)
         (liftIO . hClose)
@@ -121,7 +128,7 @@ sourceTLSDataCommand
     -> (FTP.Handle -> ConduitM i o m r)
     -> ConduitM i o m r
 sourceTLSDataCommand ch pa code cmd f = do
-    sendCommandS ch $ RType code
+    _ <- sendCommandS ch $ RType code
     x <- bracketP
         (createTLSSendDataCommand ch pa cmd)
         (liftIO . connectionClose)
@@ -130,9 +137,13 @@ sourceTLSDataCommand ch pa code cmd f = do
     debugResponse resp
     return x
 
-sourceFTPHandle :: MonadIO m => FTP.Handle -> Producer m ByteString
-sourceFTPHandle h = loop
-    where
+sourceFTPHandle
+    :: forall i m
+     . MonadIO m
+    => FTP.Handle
+    -> ConduitT i ByteString m ()
+sourceFTPHandle h =
+    let loop :: ConduitT i ByteString m ()
         loop = do
             bs <- liftIO $ FTP.recv h defaultChunkSize
                 `M.catchIOError` const (return "")
@@ -141,10 +152,15 @@ sourceFTPHandle h = loop
                 else do
                     yield bs
                     loop
+    in loop
 
-sinkFTPHandle :: MonadIO m => FTP.Handle -> Consumer ByteString m ()
-sinkFTPHandle h = loop
-    where
+sinkFTPHandle
+    :: forall o m
+     . MonadIO m
+    => FTP.Handle
+    -> ConduitT ByteString o m ()
+sinkFTPHandle h =
+    let loop :: ConduitT ByteString o m ()
         loop = do
             mbs <- await
             case mbs of
@@ -152,24 +168,25 @@ sinkFTPHandle h = loop
                 Just bs -> do
                     liftIO $ FTP.send h bs
                     loop
+    in loop
 
 sendType
     :: MonadResource m
     => RTypeCode
     -> FTP.Handle
-    -> Consumer ByteString m ()
+    -> ConduitT ByteString o m ()
 sendType TA h = sendAllLineC h
 sendType TI h = sinkFTPHandle h
 
-nlst :: MonadResource m => FTP.Handle -> [String] -> Producer m ByteString
+nlst :: MonadResource m => FTP.Handle -> [String] -> ConduitT i ByteString m ()
 nlst ch args =
     sourceDataCommandSecurity ch Passive TA (Nlst args) getAllLineRespC
 
-retr :: MonadResource m => FTP.Handle -> String -> Producer m ByteString
+retr :: MonadResource m => FTP.Handle -> String -> ConduitT i ByteString m ()
 retr ch path =
     sourceDataCommandSecurity ch Passive TI (Retr path) sourceFTPHandle
 
-list :: MonadResource m => FTP.Handle -> [String] -> Producer m ByteString
+list :: MonadResource m => FTP.Handle -> [String] -> ConduitT i ByteString m ()
 list ch args =
     sourceDataCommandSecurity ch Passive TA (List args) getAllLineRespC
 
@@ -178,7 +195,7 @@ stor
     => FTP.Handle
     -> String
     -> RTypeCode
-    -> Consumer ByteString m ()
+    -> ConduitT ByteString o m ()
 stor ch loc rtype =
     sourceDataCommandSecurity ch Passive rtype (Stor loc) $ sendType rtype
 
@@ -186,7 +203,7 @@ mlsd
     :: MonadResource m
     => FTP.Handle
     -> String
-    -> Producer m FTP.MlsxResponse
+    -> ConduitT i FTP.MlsxResponse m ()
 mlsd ch dir =
     sourceDataCommandSecurity ch Passive TA (Mlsd dir) getAllLineRespC
         .| mapC parseMlsxLine
diff --git a/ftp-client-conduit/test/Spec.hs b/ftp-client-conduit/test/Spec.hs
index cd4753f..9531f64 100644
--- a/ftp-client-conduit/test/Spec.hs
+++ b/ftp-client-conduit/test/Spec.hs
@@ -1,2 +1,6 @@
+module Main (main) where
+
+import Network.FTP.Client.Conduit ()
+
 main :: IO ()
 main = putStrLn "Test suite not yet implemented"
diff --git a/ftp-client/CHANGELOG.md b/ftp-client/CHANGELOG.md
index 8ddf20f..53f7ef4 100644
--- a/ftp-client/CHANGELOG.md
+++ b/ftp-client/CHANGELOG.md
@@ -1,5 +1,16 @@
 # Changelog for ftp-client
 
+## 0.5.3.0
+
+* Export `acct`, `pbsz`, `prot`, `ccc` and `auth`. These command wrappers were
+  defined but never exported, unlike every other command wrapper in the module.
+
+* Drop the `transformers` dependency. The only module it supplied,
+  `Control.Monad.IO.Class`, has been in `base` since 4.9.
+
+* Stop deriving `Typeable` for `FTPException`. It has been a no-op since GHC
+  7.10 and GHC 9.12 warns about it.
+
 ## 0.5.2.0
 
 * Expose `createSIOHandle`, `createTLSConnection` and `connectTLS` so callers can
diff --git a/ftp-client/ftp-client.cabal b/ftp-client/ftp-client.cabal
index b658910..902d7d8 100644
--- a/ftp-client/ftp-client.cabal
+++ b/ftp-client/ftp-client.cabal
@@ -5,7 +5,7 @@ cabal-version: 1.12
 -- see: https://github.com/sol/hpack
 
 name:           ftp-client
-version:        0.5.2.0
+version:        0.5.3.0
 synopsis:       Transfer files with FTP and FTPS
 description:    ftp-client is a library for communicating with an FTP server. It works over both a clear channel or TLS.
 category:       Web
@@ -30,6 +30,11 @@ source-repository head
   type: git
   location: https://github.com/flipstone/ftp-client
 
+flag ci
+  description: More strict ghc options used for development and ci, not intended for end-use.
+  manual: True
+  default: False
+
 library
   exposed-modules:
       Network.FTP.Client
@@ -48,8 +53,17 @@ library
     , data-default-class >=0.1.2.0 && <0.3
     , exceptions >=0.10.3 && <0.11
     , network >=2.6.3.6 && <3.3
-    , transformers >=0.5.6.2 && <0.7
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -O2 -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe -Wunused-packages
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
 
 test-suite ftp-client-test
   type: exitcode-stdio-1.0
@@ -58,10 +72,21 @@ test-suite ftp-client-test
       Paths_ftp_client
   hs-source-dirs:
       test
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base >=4.16 && <5
     , bytestring >=0.10.8.2 && <0.13
     , ftp-client
     , hspec >=2.7
   default-language: Haskell2010
+  if flag(ci)
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall -Werror -Wcompat -Widentities -Winvalid-haddock -Wmissing-local-signatures -Wmissing-export-lists -Wpartial-fields -Wmissed-specialisations -Wno-implicit-prelude -Wno-safe -Wno-unsafe
+    if impl (ghc < 9.4)
+      ghc-options: -Wno-unticked-promoted-constructors
+    if impl (ghc >= 9.4)
+      ghc-options: -Wimplicit-lift -Woperator-whitespace -Wredundant-bang-patterns -Wredundant-strictness-flags
+    if impl (ghc >= 9.8)
+      ghc-options: -Wincomplete-export-warnings -Wmissing-poly-kind-signatures -Wterm-variable-capture
+    if impl (ghc >= 9.10)
+      ghc-options: -Wdefaulted-exception-context
+  else
+    ghc-options: -threaded -rtsopts -with-rtsopts=-N
diff --git a/ftp-client/package.yaml b/ftp-client/package.yaml
index 72493b2..4d71c6b 100644
--- a/ftp-client/package.yaml
+++ b/ftp-client/package.yaml
@@ -1,5 +1,5 @@
 name:                ftp-client
-version:             0.5.2.0
+version:             0.5.3.0
 synopsis:            Transfer files with FTP and FTPS
 description:         ftp-client is a library for communicating with an FTP server. It works over both a clear channel or TLS.
 homepage:            https://github.com/flipstone/ftp-client
@@ -23,6 +23,12 @@ extra-source-files:
 
 git: https://github.com/flipstone/ftp-client
 
+flags:
+  ci:
+    description: More strict ghc options used for development and ci, not intended for end-use.
+    manual: true
+    default: false
+
 library:
   source-dirs: src
   exposed-modules:
@@ -36,22 +42,100 @@ library:
     - network >= 2.6.3.6 && < 3.3
     - attoparsec >= 0.10 && < 0.15
     - crypton-connection >= 0.3 && < 0.5
-    - transformers >= 0.5.6.2 && < 0.7
     - exceptions >= 0.10.3 && < 0.11
     - containers >= 0.5.11.0 && < 0.8
     - data-default-class >= 0.1.2.0 && < 0.3
+  when:
+    - condition: flag(ci)
+      ghc-options:
+        - -O2
+        - -Wall
+        - -Werror
+        - -Wcompat
+        - -Widentities
+        - -Winvalid-haddock
+        - -Wmissing-local-signatures
+        - -Wmissing-export-lists
+        - -Wpartial-fields
+        - -Wmissed-specialisations
+        - -Wno-implicit-prelude
+        - -Wno-safe
+        - -Wno-unsafe
+        - -Wunused-packages
+      when:
+        # Previously the guidance was to always use ticked constructors for type
+        # constructors, but that guidance has been reversed, so we turn the
+        # warning off in older compilers.
+        - condition: impl (ghc < 9.4)
+          ghc-options:
+            - -Wno-unticked-promoted-constructors
+        - condition: impl (ghc >= 9.4)
+          ghc-options:
+            - -Wimplicit-lift
+            - -Woperator-whitespace
+            - -Wredundant-bang-patterns
+            - -Wredundant-strictness-flags
+        - condition: impl (ghc >= 9.8)
+          ghc-options:
+            - -Wincomplete-export-warnings
+            - -Wmissing-poly-kind-signatures
+            - -Wterm-variable-capture
+        - condition: impl (ghc >= 9.10)
+          ghc-options:
+            - -Wdefaulted-exception-context
 
 tests:
   ftp-client-test:
     main: test.hs
     source-dirs: test
     language: Haskell2010
-    ghc-options:
-      - -threaded
-      - -rtsopts
-      - -with-rtsopts=-N
     dependencies:
       - base >= 4.16 && < 5
       - bytestring >= 0.10.8.2 && < 0.13
       - hspec >= 2.7
       - ftp-client
+    when:
+      - condition: flag(ci)
+        then:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
+            - -Wall
+            - -Werror
+            - -Wcompat
+            - -Widentities
+            - -Winvalid-haddock
+            - -Wmissing-local-signatures
+            - -Wmissing-export-lists
+            - -Wpartial-fields
+            - -Wmissed-specialisations
+            - -Wno-implicit-prelude
+            - -Wno-safe
+            - -Wno-unsafe
+          when:
+            # Previously the guidance was to always use ticked constructors for type
+            # constructors, but that guidance has been reversed, so we turn the
+            # warning off in older compilers.
+            - condition: impl (ghc < 9.4)
+              ghc-options:
+                - -Wno-unticked-promoted-constructors
+            - condition: impl (ghc >= 9.4)
+              ghc-options:
+                - -Wimplicit-lift
+                - -Woperator-whitespace
+                - -Wredundant-bang-patterns
+                - -Wredundant-strictness-flags
+            - condition: impl (ghc >= 9.8)
+              ghc-options:
+                - -Wincomplete-export-warnings
+                - -Wmissing-poly-kind-signatures
+                - -Wterm-variable-capture
+            - condition: impl (ghc >= 9.10)
+              ghc-options:
+                - -Wdefaulted-exception-context
+        else:
+          ghc-options:
+            - -threaded
+            - -rtsopts
+            - -with-rtsopts=-N
diff --git a/ftp-client/src/Network/FTP/Client.hs b/ftp-client/src/Network/FTP/Client.hs
index a9d894a..e1e33a9 100644
--- a/ftp-client/src/Network/FTP/Client.hs
+++ b/ftp-client/src/Network/FTP/Client.hs
@@ -16,6 +16,7 @@ module Network.FTP.Client (
     dele,
     cwd,
     size,
+    acct,
     mkd,
     rmd,
     pwd,
@@ -38,6 +39,11 @@ module Network.FTP.Client (
     ProtType(..),
     Security(..),
     Handle(..),
+    -- * TLS Commands
+    pbsz,
+    prot,
+    ccc,
+    auth,
     -- * Exceptions
     FTPException(..),
     -- * System Handle Creation
@@ -66,11 +72,10 @@ import Data.Default.Class (def)
 import qualified Data.ByteString.Char8 as C
 import qualified Data.ByteString as B
 import Data.ByteString (ByteString)
-import Data.List
+import Data.List (intercalate)
 import Data.Attoparsec.ByteString.Char8
 import qualified Network.Socket as S
 import qualified System.IO as SIO
-import Data.Monoid ((<>))
 import Control.Exception
 import Control.Monad.Catch (MonadCatch, MonadMask)
 import qualified Control.Monad.Catch as M
@@ -79,12 +84,9 @@ import Control.Monad.IO.Class
 import Data.Bits
 import Network.Connection
 import Data.ByteString.Lazy.Internal (defaultChunkSize)
-import Data.Functor ((<$>))
-import Control.Applicative ((<*>))
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as Map
 import Control.Arrow
-import Data.Typeable
 import System.IO.Error (isEOFError)
 
 debugging :: Bool
@@ -139,7 +141,7 @@ data FTPException
     | UnsuccessfulException FTPResponse
     | BogusResponseFormatException FTPResponse
     | BadProtocolResponseException ByteString
-    deriving (Show, Typeable)
+    deriving (Show)
 
 instance Exception FTPException
 
@@ -206,7 +208,7 @@ formatPort ha pn =
 serializeCommand :: FTPCommand -> String
 serializeCommand (User user)  = "USER " <> user
 serializeCommand (Pass pass)  = "PASS " <> pass
-serializeCommand (Acct acct)  = "ACCT " <> acct
+serializeCommand (Acct account) = "ACCT " <> account
 serializeCommand (RType rt)   = "TYPE " <> serialzeRTypeCode rt
 serializeCommand (Retr file)  = "RETR " <> file
 serializeCommand (Nlst [])    = "NLST"
@@ -267,10 +269,10 @@ getResponse h = do
         Just ('-', _) -> MultiLine <$> loopMultiLine h code [line]
         _ -> return $ SingleLine line
     let codeDroppedMessage = case message of
-            SingleLine message -> SingleLine $ C.drop 4 message
+            SingleLine singleMessage -> SingleLine $ C.drop 4 singleMessage
             MultiLine [] -> MultiLine []
-            MultiLine (message:messages) ->
-                MultiLine $ C.drop 4 message : messages
+            MultiLine (firstMessage:messages) ->
+                MultiLine $ C.drop 4 firstMessage : messages
     let response = FTPResponse
             (responseStatus code)
             (read $ C.unpack code)
@@ -286,7 +288,7 @@ loopMultiLine
     -> ByteString
     -> [ByteString]
     -> m [ByteString]
-loopMultiLine h code lines = do
+loopMultiLine h code priorLines = do
     mNextLine <- liftIO $ getLineRespMaybe h
     case mNextLine of
         -- The server hung up before sending the terminating line. Stop rather
@@ -300,13 +302,13 @@ loopMultiLine h code lines = do
         -- lines of a multiline reply hold arbitrary text, blank lines included,
         -- so a blank line has to be kept and the loop has to continue past it.
         Nothing -> liftIO $ throwIO $ BadProtocolResponseException
-            $ C.intercalate "\n" lines
+            $ C.intercalate "\n" priorLines
         Just nextLine -> do
             -- RFC 959 (https://datatracker.ietf.org/doc/html/rfc959#page-36) ends a
             -- multiline reply with the code followed by a space, and continues it
             -- with the code followed by a hyphen. The bare code is accepted too,
             -- for servers that omit the trailing space on an empty final line.
-            let newLines = lines <> [C.dropWhile (== ' ') nextLine]
+            let newLines = priorLines <> [C.dropWhile (== ' ') nextLine]
                 isLastLine =
                     nextLine == code
                         || C.isPrefixOf (code <> " ") nextLine
@@ -385,9 +387,9 @@ withSocketPassive host portNum f = do
         (createSocket (Just host) portNum hints)
         (liftIO . S.close . fst)
         (\(sock, addr) -> do
-            debugPrint "Connecting"
+            debugPrint ("Connecting" :: String)
             liftIO $ S.connect sock (S.addrAddress addr)
-            debugPrint "Connected"
+            debugPrint ("Connected" :: String)
             f sock
         )
 
@@ -401,10 +403,10 @@ withSocketActive f = do
         (createSocket Nothing 0 hints)
         (liftIO . S.close . fst)
         (\(sock, addr) -> do
-            debugPrint "Binding"
+            debugPrint ("Binding" :: String)
             liftIO $ S.bind sock (S.addrAddress addr)
             liftIO $ S.listen sock 1
-            debugPrint "Listening"
+            debugPrint ("Listening" :: String)
             f sock
         )
 
@@ -471,9 +473,9 @@ withDataSocketActive
     -> m a
 withDataSocketActive h f = withSocketActive $ \socket -> do
     (sPort, sHost) <- liftIO $ do
-      (S.SockAddrInet p h) <- S.getSocketName socket
-      return (p,h)
-    port h sHost sPort
+      (S.SockAddrInet p hostAddr) <- S.getSocketName socket
+      return (p,hostAddr)
+    _ <- port h sHost sPort
     f socket
 
 -- | Open a socket that can be used for data transfers
@@ -527,7 +529,7 @@ withDataCommand
     -> (Handle -> m a)
     -> m a
 withDataCommand ch pa code cmd f = do
-    sendCommandS ch $ RType code
+    _ <- sendCommandS ch $ RType code
     x <- M.bracket
         (createSendDataCommand ch pa cmd)
         (liftIO . SIO.hClose)
@@ -538,32 +540,35 @@ withDataCommand ch pa code cmd f = do
 
 -- | Recieve data and interpret it linewise
 getAllLineResp :: (MonadIO m, MonadCatch m) => Handle -> m ByteString
-getAllLineResp h = getAllLineResp' h []
-    where
-        getAllLineResp' h ret = ( do
+getAllLineResp h =
+    let collect :: (MonadIO n, MonadCatch n) => [ByteString] -> n ByteString
+        collect ret = ( do
             line <- liftIO $ getLineResp h
-            getAllLineResp' h (ret <> [line]))
+            collect (ret <> [line]))
                 `M.catchIOError` (\_ -> return $ C.intercalate "\n" ret)
+    in collect []
 
 -- | Recieve all data and return it as a 'Data.ByteString.ByteString'
 recvAll :: (MonadIO m, MonadCatch m) => Handle -> m ByteString
-recvAll h = recvAll' ""
-    where
-        recvAll' bs = ( do
+recvAll h =
+    let collect :: (MonadIO n, MonadCatch n) => ByteString -> n ByteString
+        collect bs = ( do
             chunk <- liftIO $ recv h defaultChunkSize
             if C.null chunk
                then return bs
-               else recvAll' $ bs <> chunk
+               else collect $ bs <> chunk
             ) `M.catchIOError` (\_ -> return bs)
+    in collect ""
 
 -- TLS connection
 
 connectTLS :: MonadIO m => SIO.Handle -> String -> Int -> m Connection
 connectTLS h host portNum = do
     context <- liftIO initConnectionContext
-    let tlsSettings = def
-            { settingDisableCertificateValidation = True
-            }
+    let tlsSettings = case def of
+            simpleSettings@TLSSettingsSimple{} ->
+                simpleSettings { settingDisableCertificateValidation = True }
+            otherSettings -> otherSettings
         connectionParams = ConnectionParams
             { connectionHostname = host
             , connectionPort = toEnum . fromEnum $ portNum
@@ -581,7 +586,7 @@ createTLSConnection host portNum = do
     h <- createSIOHandle host portNum
     let insecureH = sIOHandleImpl h
     resp <- getResponse insecureH
-    sendCommand insecureH Auth
+    _ <- sendCommand insecureH Auth
     conn <- connectTLS h host portNum
     return (resp, conn)
 
@@ -633,7 +638,7 @@ createTLSSendDataCommand
     -> FTPCommand
     -> m Connection
 createTLSSendDataCommand ch pa cmd = do
-    sendAllS ch [Pbsz 0, Prot P]
+    _ <- sendAllS ch [Pbsz 0, Prot P]
     withDataSocket pa ch $ \socket -> do
         resp <- sendCommand ch cmd
         ensureSucessfulData ch resp
@@ -655,7 +660,7 @@ withTLSDataCommand
     -> (Handle -> m a)
     -> m a
 withTLSDataCommand ch pa code cmd f = do
-    sendCommandS ch $ RType code
+    _ <- sendCommandS ch $ RType code
     x <- M.bracket
         (createTLSSendDataCommand ch pa cmd)
         (liftIO . connectionClose)
@@ -681,7 +686,7 @@ ensureCode resp code =
 
 parse227 :: Parser (String, Int)
 parse227 = do
-    skipWhile (/= '(') *> char '('
+    _ <- skipWhile (/= '(') *> char '('
     [h1,h2,h3,h4,p1,p2] <- many1 digit `sepBy` char ','
     let host = intercalate "." [h1,h2,h3,h4]
         highBits = read p1
@@ -691,7 +696,7 @@ parse227 = do
 
 parse257 :: Parser String
 parse257 = do
-    char '"'
+    _ <- char '"'
     C.unpack <$> takeTill (== '"')
 
 -- Control commands
@@ -837,15 +842,16 @@ parseMlsxLine line =
     in MlsxResponse (C.unpack filename) facts
 
 getMlsxResponse :: (MonadIO m, MonadCatch m) => Handle -> m [MlsxResponse]
-getMlsxResponse h = getMlsxResponse' h []
-    where
-        getMlsxResponse' h ret = ( do
+getMlsxResponse h =
+    let collect :: (MonadIO n, MonadCatch n) => [MlsxResponse] -> n [MlsxResponse]
+        collect ret = ( do
             line <- liftIO $ getLineResp h
-            getMlsxResponse' h $
+            collect $
                 if C.null line
                     then ret
                     else parseMlsxLine line : ret
             ) `M.catchIOError` (\_ -> return ret)
+    in collect []
 
 mlsd :: (MonadIO m, MonadMask m) => Handle -> String -> m [MlsxResponse]
 mlsd h path = withDataCommandSecurity h Passive TA (Mlsd path) getMlsxResponse
diff --git a/ftp-client/test/test.hs b/ftp-client/test/test.hs
index c4738b9..aac5058 100644
--- a/ftp-client/test/test.hs
+++ b/ftp-client/test/test.hs
@@ -1,16 +1,17 @@
+module Main (main) where
+
 import Data.ByteString (ByteString)
 import qualified Data.ByteString.Char8 as C
 import Test.Hspec
 import Network.FTP.Client hiding (Success)
 import qualified Network.FTP.Client as F
-import Control.Monad.IO.Class
 import Control.Concurrent.MVar
 import System.IO.Error (eofErrorType, mkIOError)
 
 data TestHandleMVars = TestHandleMVars
     { thmSend :: MVar [ByteString]
-    , thmSendLine :: MVar [ByteString]
-    , thmRecv :: MVar [Int]
+    , _thmSendLine :: MVar [ByteString]
+    , _thmRecv :: MVar [Int]
     }
 
 data TestHandle = TestHandle TestHandleMVars Handle
@@ -156,7 +157,7 @@ main = hspec $ do
     describe "Network.FTP.Client.recvAll" $
         it "doesn't hang on empty response" $ do
             let expected = C.pack ""
-            (TestHandle mvars h) <- testHandle [C.pack ""] [] Clear
+            (TestHandle _ h) <- testHandle [C.pack ""] [] Clear
             recvAll h `shouldReturn` expected
 
 isBadProtocolResponse :: FTPException -> Bool
diff --git a/stack-base.yaml b/stack-base.yaml
index b7fa0aa..f622551 100644
--- a/stack-base.yaml
+++ b/stack-base.yaml
@@ -3,4 +3,12 @@ packages:
   - 'ftp-client-conduit'
   - 'example'
 
+flags:
+  ftp-client:
+    ci: true
+  ftp-client-conduit:
+    ci: true
+  example:
+    ci: true
+
 pvp-bounds: both