diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,18 @@
 See also http://pvp.haskell.org/faq
 
+0.6.2.5
+-------
+
+* Allow `Cabal-3.12` and `Cabal-syntax-3.12`.
+* Allow `zlib-0.7`.
+* Drop flag `use-old-time` and support for `old-time`, require `time ≥ 1.5`
+  ([PR #304](https://github.com/haskell/hackage-security/pull/304)).
+* Drop support for GHC < 8.4
+  ([PR #306](https://github.com/haskell/hackage-security/pull/306)).
+* Code maintenance: address warning `star-is-type`, `unused-record-wildcards` etc.
+  ([PR #306](https://github.com/haskell/hackage-security/pull/306)).
+* Tested with GHC 8.4 - 9.8.
+
 0.6.2.4
 -------
 
diff --git a/hackage-security.cabal b/hackage-security.cabal
--- a/hackage-security.cabal
+++ b/hackage-security.cabal
@@ -1,6 +1,6 @@
 cabal-version:       1.12
 name:                hackage-security
-version:             0.6.2.4
+version:             0.6.2.5
 
 synopsis:            Hackage security library
 description:         The hackage security library provides both server and
@@ -31,8 +31,8 @@
 build-type:          Simple
 
 tested-with:
-  GHC == 9.8.1
-  GHC == 9.6.3
+  GHC == 9.8.2
+  GHC == 9.6.4
   GHC == 9.4.8
   GHC == 9.2.8
   GHC == 9.0.2
@@ -40,9 +40,6 @@
   GHC == 8.8.4
   GHC == 8.6.5
   GHC == 8.4.4
-  GHC == 8.2.2
-  GHC == 8.0.2
-  GHC == 7.10.3
 
 extra-source-files:
   ChangeLog.md
@@ -110,41 +107,38 @@
                        Hackage.Security.Util.Lens
                        Hackage.Security.Util.Stack
                        Hackage.Security.Util.TypedEmbedded
-                       MyPrelude
-  -- We support ghc 7.4 (bundled with Cabal 1.14) and up
-  build-depends:       base              >= 4.8     && < 4.20,
-                         -- PatternSynonyms are only available since GHC 7.8 (base 4.7)
-                       base16-bytestring >= 0.1.1   && < 1.1,
-                       base64-bytestring >= 1.0     && < 1.3,
-                       bytestring        >= 0.9     && < 0.13,
-                       containers        >= 0.4     && < 0.8,
-                       cryptohash-sha256 >= 0.11    && < 0.12,
-                       directory         >= 1.2     && < 1.4,
-                       ed25519           >= 0.0     && < 0.1,
-                       filepath          >= 1.2     && < 1.5,
-                       mtl               >= 2.2     && < 2.4,
-                       parsec            >= 3.1     && < 3.2,
-                       pretty            >= 1.0     && < 1.2,
+
+  build-depends:       base              >= 4.11     && < 4.20,
+                       base16-bytestring >= 0.1.1    && < 1.1,
+                       base64-bytestring >= 1.0      && < 1.3,
+                       bytestring        >= 0.10.8.2 && < 0.13,
+                       containers        >= 0.5.11   && < 0.8,
+                       cryptohash-sha256 >= 0.11     && < 0.12,
+                       directory         >= 1.3.1.5  && < 1.4,
+                       ed25519           >= 0.0      && < 0.1,
+                       filepath          >= 1.4.2    && < 1.5,
+                       mtl               >= 2.2.2    && < 2.4,
+                       parsec            >= 3.1.13   && < 3.2,
+                       pretty            >= 1.0      && < 1.2,
                        -- 0.4.2 introduces TarIndex, 0.4.4 introduces more
                        -- functionality, 0.5.0 changes type of serialise
-                       tar               >= 0.5     && < 0.7,
-                       template-haskell  >= 2.7     && < 2.22,
-                       time              >= 1.2     && < 1.13,
-                       transformers      >= 0.3     && < 0.7,
-                       zlib              >= 0.5     && < 0.7,
+                       tar               >= 0.5      && < 0.7,
+                       template-haskell  >= 2.13     && < 2.22,
+                       time              >= 1.8.0.2  && < 1.13,
+                       transformers      >= 0.3      && < 0.7,
+                       zlib              >= 0.5     && < 0.8,
                        -- whatever versions are bundled with ghc:
-                       ghc-prim
+                       ghc-prim          >= 0.5.2    && < 0.12
 
   if flag(lukko)
     build-depends:     lukko      >= 0.1     && < 0.2
   else
-    build-depends:     base       >= 4.10
+    build-depends:     base       >= 4.11
 
-  if flag(Cabal-syntax) && impl(ghc >= 8.2)
-    build-depends: Cabal-syntax >= 3.7 && < 3.12
+  if flag(Cabal-syntax)
+    build-depends: Cabal-syntax >= 3.7 && < 3.14
   else
-    build-depends: Cabal        >= 1.14    && < 1.26
-                             || >= 2.0     && < 2.6
+    build-depends: Cabal        >= 2.2.0.1 && < 2.6
                              || >= 3.0     && < 3.7,
                    Cabal-syntax <  3.7
 
@@ -175,18 +169,13 @@
                        AllowAmbiguousTypes
                        BangPatterns
                        CPP
+                       DeriveLift
                        OverlappingInstances
                        PackageImports
                        RoleAnnotations
                        StaticPointers
                        UndecidableInstances
 
-  -- use the new stage1/cross-compile-friendly DeriveLift extension for GHC 8.0+
-  if impl(ghc >= 8.0)
-    other-extensions: DeriveLift
-  else
-    other-extensions: TemplateHaskell
-
   ghc-options:         -Wall
 
   -- The URI type got split out off the network package after version 2.5, and
@@ -250,12 +239,11 @@
                        time,
                        zlib
 
-  if flag(Cabal-syntax) && impl(ghc >= 8.2)
-    build-depends: Cabal        >= 3.7 && < 3.12,
-                   Cabal-syntax >= 3.7 && < 3.12
+  if flag(Cabal-syntax)
+    build-depends: Cabal        >= 3.7 && < 3.14,
+                   Cabal-syntax >= 3.7 && < 3.14
   else
-    build-depends: Cabal        >= 1.14    && < 1.26
-                             || >= 2.0     && < 2.6
+    build-depends: Cabal        >= 2.2.0.1 && < 2.6
                              || >= 3.0     && < 3.7,
                    Cabal-syntax <  3.7
 
diff --git a/src/Hackage/Security/Client.hs b/src/Hackage/Security/Client.hs
--- a/src/Hackage/Security/Client.hs
+++ b/src/Hackage/Security/Client.hs
@@ -1,7 +1,5 @@
-{-# LANGUAGE CPP #-}
-#if __GLASGOW_HASKELL__ >= 710
 {-# LANGUAGE StaticPointers #-}
-#endif
+
 -- | Main entry point into the Hackage Security framework for clients
 module Hackage.Security.Client (
     -- * Checking for updates
@@ -41,7 +39,7 @@
   , LocalFileCorrupted(..)
   ) where
 
-import MyPrelude hiding (log)
+import Prelude hiding (log)
 import Control.Arrow (first)
 import Control.Exception
 import Control.Monad
@@ -333,11 +331,7 @@
 
 -- | Get all cached info (if any)
 getCachedInfo ::
-#if __GLASGOW_HASKELL__ < 800
-                 (Applicative m, MonadIO m)
-#else
                  MonadIO m
-#endif
               => Repository down -> m CachedInfo
 getCachedInfo rep = do
     (cachedRoot, cachedKeyEnv) <- readLocalRoot rep
@@ -360,9 +354,6 @@
     return (trustLocalFile signedRoot, rootKeys (signed signedRoot))
 
 readLocalFile :: ( FromJSON ReadJSON_Keys_Layout (Signed a), MonadIO m
-#if __GLASGOW_HASKELL__ < 800
-                 , Applicative m
-#endif
                  )
               => Repository down -> KeyEnv -> CachedFile -> m (Maybe (Trusted a))
 readLocalFile rep cachedKeyEnv file = do
@@ -383,7 +374,7 @@
               -> Maybe UTCTime
               -> RemoteFile (f :- ()) Metadata
               -> Verify (Trusted a, down Metadata)
-getRemoteFile rep@Repository{..} cachedInfo@CachedInfo{..} isRetry mNow file = do
+getRemoteFile rep@Repository{} cachedInfo@CachedInfo{..} isRetry mNow file = do
     (targetPath, tempPath) <- getRemote' rep isRetry file
     verifyFileInfo' (remoteFileDefaultInfo file) targetPath tempPath
     signed   <- throwErrorsChecked (VerificationErrorDeserialization targetPath) =<<
@@ -952,21 +943,12 @@
   }
   deriving (Typeable)
 
-#if MIN_VERSION_base(4,8,0)
 deriving instance Show InvalidPackageException
 deriving instance Show LocalFileCorrupted
 deriving instance Show InvalidFileInIndex
 instance Exception InvalidPackageException where displayException = pretty
 instance Exception LocalFileCorrupted where displayException = pretty
 instance Exception InvalidFileInIndex where displayException = pretty
-#else
-instance Show InvalidPackageException where show = pretty
-instance Show LocalFileCorrupted where show = pretty
-instance Show InvalidFileInIndex where show = pretty
-instance Exception InvalidPackageException
-instance Exception LocalFileCorrupted
-instance Exception InvalidFileInIndex
-#endif
 
 instance Pretty InvalidPackageException where
   pretty (InvalidPackageException pkgId) = "Invalid package " ++ display pkgId
diff --git a/src/Hackage/Security/Client/Formats.hs b/src/Hackage/Security/Client/Formats.hs
--- a/src/Hackage/Security/Client/Formats.hs
+++ b/src/Hackage/Security/Client/Formats.hs
@@ -17,7 +17,8 @@
   , formatsLookup
   ) where
 
-import MyPrelude
+import Prelude
+import Data.Kind (Type)
 import Hackage.Security.Util.Stack
 import Hackage.Security.Util.TypedEmbedded
 
@@ -31,7 +32,7 @@
 -- | Format is a singleton type (reflection type to term level)
 --
 -- NOTE: In the future we might add further compression formats.
-data Format :: * -> * where
+data Format :: Type -> Type where
   FUn :: Format FormatUn
   FGz :: Format FormatGz
 
@@ -55,7 +56,7 @@
 --
 -- NOTE: If we add additional cases here (for dealing with additional formats)
 -- all calls to @error "inaccessible"@ need to be reevaluated.
-data Formats :: * -> * -> * where
+data Formats :: Type -> Type -> Type where
   FsNone :: Formats () a
   FsUn   :: a -> Formats (FormatUn :- ()) a
   FsGz   :: a -> Formats (FormatGz :- ()) a
@@ -74,7 +75,7 @@
 -- | @HasFormat fs f@ is a proof that @f@ is a key in @fs@.
 --
 -- See 'formatsMember' and 'formatsLookup' for typical usage.
-data HasFormat :: * -> * -> * where
+data HasFormat :: Type -> Type -> Type where
   HFZ :: Format f       -> HasFormat (f  :- fs) f
   HFS :: HasFormat fs f -> HasFormat (f' :- fs) f
 
diff --git a/src/Hackage/Security/Client/Repository.hs b/src/Hackage/Security/Client/Repository.hs
--- a/src/Hackage/Security/Client/Repository.hs
+++ b/src/Hackage/Security/Client/Repository.hs
@@ -30,8 +30,9 @@
   , mustCache
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Exception
+import Data.Kind (Type)
 import Data.Typeable (Typeable)
 import qualified Codec.Archive.Tar.Index as Tar
 import qualified Data.ByteString.Lazy    as BS.L
@@ -63,7 +64,7 @@
 -- is metadata actual binary content.
 --
 -- NOTE: Haddock lacks GADT support so constructors have only regular comments.
-data RemoteFile :: * -> * -> * where
+data RemoteFile :: Type -> Type -> Type where
     -- Timestamp metadata (@timestamp.json@)
     --
     -- We never have (explicit) file length available for timestamps.
@@ -361,7 +362,7 @@
   Downloaded files
 -------------------------------------------------------------------------------}
 
-class DownloadedFile (down :: * -> *) where
+class DownloadedFile (down :: Type -> Type) where
   -- | Verify a download file
   downloadedVerify :: down a -> Trusted FileInfo -> IO Bool
 
@@ -381,17 +382,12 @@
 --
 -- For instance, for repositories using HTTP this might correspond to a 404;
 -- for local repositories this might correspond to file-not-found, etc.
-data SomeRemoteError :: * where
+data SomeRemoteError :: Type where
     SomeRemoteError :: Exception e => e -> SomeRemoteError
   deriving (Typeable)
 
-#if MIN_VERSION_base(4,8,0)
 deriving instance Show SomeRemoteError
 instance Exception SomeRemoteError where displayException = pretty
-#else
-instance Exception SomeRemoteError
-instance Show SomeRemoteError where show = pretty
-#endif
 
 instance Pretty SomeRemoteError where
     pretty (SomeRemoteError ex) = displayException ex
@@ -424,7 +420,7 @@
 -------------------------------------------------------------------------------}
 
 -- | Is a particular remote file cached?
-data IsCached :: * -> * where
+data IsCached :: Type -> Type where
     -- This remote file should be cached, and we ask for it by name
     CacheAs :: CachedFile -> IsCached Metadata
 
diff --git a/src/Hackage/Security/Client/Repository/Cache.hs b/src/Hackage/Security/Client/Repository/Cache.hs
--- a/src/Hackage/Security/Client/Repository/Cache.hs
+++ b/src/Hackage/Security/Client/Repository/Cache.hs
@@ -15,7 +15,7 @@
   , lockCacheWithLogger
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Exception
 import Control.Monad
 import Control.Monad.IO.Class
diff --git a/src/Hackage/Security/Client/Repository/HttpLib.hs b/src/Hackage/Security/Client/Repository/HttpLib.hs
--- a/src/Hackage/Security/Client/Repository/HttpLib.hs
+++ b/src/Hackage/Security/Client/Repository/HttpLib.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 -- | Abstracting over HTTP libraries
 module Hackage.Security.Client.Repository.HttpLib (
     HttpLib(..)
@@ -11,7 +10,7 @@
   , bodyReaderFromBS
   ) where
 
-import MyPrelude
+import Prelude
 import Data.IORef
 import Network.URI hiding (uriPath, path)
 import qualified Data.ByteString      as BS
diff --git a/src/Hackage/Security/Client/Repository/Local.hs b/src/Hackage/Security/Client/Repository/Local.hs
--- a/src/Hackage/Security/Client/Repository/Local.hs
+++ b/src/Hackage/Security/Client/Repository/Local.hs
@@ -5,7 +5,7 @@
   , withRepository
   ) where
 
-import MyPrelude
+import Prelude
 import Hackage.Security.Client.Formats
 import Hackage.Security.Client.Repository
 import Hackage.Security.Client.Repository.Cache
diff --git a/src/Hackage/Security/Client/Repository/Remote.hs b/src/Hackage/Security/Client/Repository/Remote.hs
--- a/src/Hackage/Security/Client/Repository/Remote.hs
+++ b/src/Hackage/Security/Client/Repository/Remote.hs
@@ -27,11 +27,12 @@
   , fileSizeWithinBounds
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Concurrent
 import Control.Exception
 import Control.Monad (when, unless)
 import Control.Monad.IO.Class (MonadIO)
+import Data.Kind (Type)
 import Data.List (nub, intercalate)
 import Data.Typeable
 import Network.URI hiding (uriPath, path)
@@ -238,7 +239,7 @@
 -- error we want to make sure caches get files upstream in case the validation
 -- error was because the cache updated files out of order.
 httpRequestHeaders :: RemoteConfig -> AttemptNr -> [HttpRequestHeader]
-httpRequestHeaders RemoteConfig{..} attemptNr =
+httpRequestHeaders RemoteConfig{} attemptNr =
     if attemptNr == 0 then defaultHeaders
                       else HttpRequestMaxAge0 : defaultHeaders
   where
@@ -256,7 +257,7 @@
            -> Maybe [Mirror]         -- ^ TUF mirrors
            -> IO a                   -- ^ Callback
            -> IO a
-withMirror HttpLib{..}
+withMirror HttpLib{}
            selectedMirror
            logger
            oobMirrors
@@ -300,7 +301,7 @@
 -------------------------------------------------------------------------------}
 
 -- | Download method (downloading or updating)
-data DownloadMethod :: * -> * -> * where
+data DownloadMethod :: Type -> Type -> Type where
     -- Download this file (we never attempt to update this type of file)
     NeverUpdated :: {
         neverUpdatedFormat :: HasFormat fs f
@@ -498,13 +499,8 @@
       expected (FileSizeExact n) = "exactly " ++ show n
       expected (FileSizeBound n) = "at most " ++ show n
 
-#if MIN_VERSION_base(4,8,0)
 deriving instance Show FileTooLarge
 instance Exception FileTooLarge where displayException = pretty
-#else
-instance Exception FileTooLarge
-instance Show FileTooLarge where show = pretty
-#endif
 
 {-------------------------------------------------------------------------------
   Information about remote files
@@ -600,7 +596,7 @@
   Files downloaded from the remote repository
 -------------------------------------------------------------------------------}
 
-data RemoteTemp :: * -> * where
+data RemoteTemp :: Type -> Type where
     DownloadedWhole :: {
         wholeTemp :: Path Absolute
       } -> RemoteTemp a
@@ -687,4 +683,3 @@
                 BS.L.take (fromIntegral deltaSeek) existing
               , temp
               ]
-
diff --git a/src/Hackage/Security/Client/Verify.hs b/src/Hackage/Security/Client/Verify.hs
--- a/src/Hackage/Security/Client/Verify.hs
+++ b/src/Hackage/Security/Client/Verify.hs
@@ -10,7 +10,7 @@
   , liftIO
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Exception
 import Control.Monad (join, void)
 import Control.Monad.IO.Class (MonadIO, liftIO)
diff --git a/src/Hackage/Security/JSON.hs b/src/Hackage/Security/JSON.hs
--- a/src/Hackage/Security/JSON.hs
+++ b/src/Hackage/Security/JSON.hs
@@ -38,7 +38,7 @@
   , module Hackage.Security.Util.JSON
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Arrow (first, second)
 import Control.Exception
 import Control.Monad (unless, liftM)
@@ -84,13 +84,8 @@
   | DeserializationErrorFileType String String
   deriving (Typeable)
 
-#if MIN_VERSION_base(4,8,0)
 deriving instance Show DeserializationError
 instance Exception DeserializationError where displayException = pretty
-#else
-instance Show DeserializationError where show = pretty
-instance Exception DeserializationError
-#endif
 
 instance Pretty DeserializationError where
   pretty (DeserializationErrorMalformed str) =
diff --git a/src/Hackage/Security/Key.hs b/src/Hackage/Security/Key.hs
--- a/src/Hackage/Security/Key.hs
+++ b/src/Hackage/Security/Key.hs
@@ -25,7 +25,7 @@
   , verify
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Monad
 import Data.Functor.Identity
 import Data.Typeable (Typeable)
@@ -37,10 +37,6 @@
 import qualified Data.ByteString.Base16 as Base16
 import qualified Data.ByteString.Lazy as BS.L
 
-#if !MIN_VERSION_base(4,7,0)
-import qualified Data.Typeable as Typeable
-#endif
-
 import Hackage.Security.Util.JSON
 import Hackage.Security.Util.Some
 import Hackage.Security.Util.TypedEmbedded
@@ -277,26 +273,3 @@
     case tag of
       "ed25519"  -> return . Some $ KeyTypeEd25519
       _otherwise -> expected "valid key type" (Just tag)
-
-{-------------------------------------------------------------------------------
-  Orphans
-
-  Pre-7.8 (base 4.7) we cannot have Typeable instance for higher-kinded types.
-  Instead, here we provide some instance for specific instantiations.
--------------------------------------------------------------------------------}
-
-#if !MIN_VERSION_base(4,7,0)
-tyConKey, tyConPublicKey, tyConPrivateKey :: Typeable.TyCon
-tyConKey        = Typeable.mkTyCon3 "hackage-security" "Hackage.Security.Key" "Key"
-tyConPublicKey  = Typeable.mkTyCon3 "hackage-security" "Hackage.Security.Key" "PublicKey"
-tyConPrivateKey = Typeable.mkTyCon3 "hackage-security" "Hackage.Security.Key" "PrivateKey"
-
-instance Typeable (Some Key) where
-  typeOf _ = Typeable.mkTyConApp tyConSome [Typeable.mkTyConApp tyConKey []]
-
-instance Typeable (Some PublicKey) where
-  typeOf _ = Typeable.mkTyConApp tyConSome [Typeable.mkTyConApp tyConPublicKey []]
-
-instance Typeable (Some PrivateKey) where
-  typeOf _ = Typeable.mkTyConApp tyConSome [Typeable.mkTyConApp tyConPrivateKey []]
-#endif
diff --git a/src/Hackage/Security/Key/Env.hs b/src/Hackage/Security/Key/Env.hs
--- a/src/Hackage/Security/Key/Env.hs
+++ b/src/Hackage/Security/Key/Env.hs
@@ -12,7 +12,7 @@
   , union
   ) where
 
-import MyPrelude hiding (lookup, null)
+import Prelude hiding (lookup, null)
 import Control.Monad
 import Data.Map (Map)
 import qualified Data.Map as Map
diff --git a/src/Hackage/Security/TUF/Common.hs b/src/Hackage/Security/TUF/Common.hs
--- a/src/Hackage/Security/TUF/Common.hs
+++ b/src/Hackage/Security/TUF/Common.hs
@@ -6,7 +6,7 @@
   , KeyThreshold(..)
   ) where
 
-import MyPrelude
+import Prelude
 import Hackage.Security.JSON
 
 {-------------------------------------------------------------------------------
diff --git a/src/Hackage/Security/TUF/FileInfo.hs b/src/Hackage/Security/TUF/FileInfo.hs
--- a/src/Hackage/Security/TUF/FileInfo.hs
+++ b/src/Hackage/Security/TUF/FileInfo.hs
@@ -13,7 +13,7 @@
   , Int54
   ) where
 
-import MyPrelude hiding (lookup)
+import Prelude hiding (lookup)
 import Data.Map (Map)
 import qualified Crypto.Hash.SHA256   as SHA256
 import qualified Data.Map             as Map
diff --git a/src/Hackage/Security/TUF/FileMap.hs b/src/Hackage/Security/TUF/FileMap.hs
--- a/src/Hackage/Security/TUF/FileMap.hs
+++ b/src/Hackage/Security/TUF/FileMap.hs
@@ -18,7 +18,7 @@
   , fileMapChanges
   ) where
 
-import MyPrelude hiding (lookup)
+import Prelude hiding (lookup)
 import Control.Arrow (second)
 import Data.Map (Map)
 import qualified Data.Map as Map
diff --git a/src/Hackage/Security/TUF/Header.hs b/src/Hackage/Security/TUF/Header.hs
--- a/src/Hackage/Security/TUF/Header.hs
+++ b/src/Hackage/Security/TUF/Header.hs
@@ -12,7 +12,7 @@
   , versionIncrement
   ) where
 
-import MyPrelude
+import Prelude
 import Data.Time
 import Data.Typeable (Typeable)
 
diff --git a/src/Hackage/Security/TUF/Layout/Cache.hs b/src/Hackage/Security/TUF/Layout/Cache.hs
--- a/src/Hackage/Security/TUF/Layout/Cache.hs
+++ b/src/Hackage/Security/TUF/Layout/Cache.hs
@@ -4,7 +4,7 @@
   , cabalCacheLayout
   ) where
 
-import MyPrelude
+import Prelude
 import Hackage.Security.TUF.Paths
 import Hackage.Security.Util.Path
 
diff --git a/src/Hackage/Security/TUF/Layout/Index.hs b/src/Hackage/Security/TUF/Layout/Index.hs
--- a/src/Hackage/Security/TUF/Layout/Index.hs
+++ b/src/Hackage/Security/TUF/Layout/Index.hs
@@ -9,7 +9,8 @@
   , indexLayoutPkgPrefs
   ) where
 
-import MyPrelude
+import Prelude
+import Data.Kind (Type)
 import Distribution.Package
 import Distribution.Text
 
@@ -43,7 +44,7 @@
 -- TODO: If we wanted to support legacy Hackage, we should also have a case for
 -- the global preferred-versions file. But supporting legacy Hackage will
 -- probably require more work anyway..
-data IndexFile :: * -> * where
+data IndexFile :: Type -> Type where
     -- Package-specific metadata (@targets.json@)
     IndexPkgMetadata :: PackageIdentifier -> IndexFile (Signed Targets)
 
diff --git a/src/Hackage/Security/TUF/Layout/Repo.hs b/src/Hackage/Security/TUF/Layout/Repo.hs
--- a/src/Hackage/Security/TUF/Layout/Repo.hs
+++ b/src/Hackage/Security/TUF/Layout/Repo.hs
@@ -5,7 +5,7 @@
   , cabalLocalRepoLayout
   ) where
 
-import MyPrelude
+import Prelude
 import Distribution.Package
 import Distribution.Text
 
diff --git a/src/Hackage/Security/TUF/Mirrors.hs b/src/Hackage/Security/TUF/Mirrors.hs
--- a/src/Hackage/Security/TUF/Mirrors.hs
+++ b/src/Hackage/Security/TUF/Mirrors.hs
@@ -9,7 +9,7 @@
   , describeMirror
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Monad.Except
 import Network.URI
 
diff --git a/src/Hackage/Security/TUF/Paths.hs b/src/Hackage/Security/TUF/Paths.hs
--- a/src/Hackage/Security/TUF/Paths.hs
+++ b/src/Hackage/Security/TUF/Paths.hs
@@ -14,7 +14,7 @@
   , anchorCachePath
   ) where
 
-import MyPrelude
+import Prelude
 import Hackage.Security.Util.Path
 import Hackage.Security.Util.Pretty
 
diff --git a/src/Hackage/Security/TUF/Patterns.hs b/src/Hackage/Security/TUF/Patterns.hs
--- a/src/Hackage/Security/TUF/Patterns.hs
+++ b/src/Hackage/Security/TUF/Patterns.hs
@@ -2,13 +2,9 @@
 --
 -- NOTE: This module was developed to prepare for proper delegation (#39).
 -- It is currently unused.
-{-# LANGUAGE CPP #-}
-#if __GLASGOW_HASKELL__ >= 800
 {-# LANGUAGE DeriveLift #-}
 {-# LANGUAGE StandaloneDeriving #-}
-#else
-{-# LANGUAGE TemplateHaskell #-}
-#endif
+
 module Hackage.Security.TUF.Patterns (
     -- * Patterns and replacements
     FileName
@@ -26,7 +22,7 @@
   , qqd
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Monad (guard)
 import Language.Haskell.TH (Q, Exp)
 import System.FilePath.Posix
@@ -130,8 +126,8 @@
     go []    _                    = Nothing
     go [f]   (PatFileConst f')    = do guard (f == f')
                                        return ()
-    go [f]   (PatFileExt   e')    = do let (bn, _:e) = splitExtension f
-                                       guard $ e == e'
+    go [f]   (PatFileExt   e')    = do let (bn, dotExt) = splitExtension f
+                                       guard $ dotExt == '.':e'
                                        return (bn :- ())
     go [_]   _                    = Nothing
     go (d:p) (PatDirConst  d' p') = do guard (d == d')
@@ -274,29 +270,10 @@
       Left  err -> fail $ "Invalid delegation: " ++ err
       Right del -> TH.lift del
 
-#if __GLASGOW_HASKELL__ >= 800
 deriving instance TH.Lift (Pattern a)
 deriving instance TH.Lift (Replacement a)
 deriving instance TH.Lift Delegation
-#else
-instance TH.Lift (Pattern a) where
-  lift (PatFileConst fn)  = [| PatFileConst fn  |]
-  lift (PatFileExt   e)   = [| PatFileExt   e   |]
-  lift PatFileAny         = [| PatFileAny       |]
-  lift (PatDirConst  d p) = [| PatDirConst  d p |]
-  lift (PatDirAny      p) = [| PatDirAny      p |]
 
-instance TH.Lift (Replacement a) where
-  lift (RepFileConst fn)  = [| RepFileConst fn  |]
-  lift (RepFileExt   e )  = [| RepFileExt   e   |]
-  lift RepFileAny         = [| RepFileAny       |]
-  lift (RepDirConst  d r) = [| RepDirConst  d r |]
-  lift (RepDirAny      r) = [| RepDirAny      r |]
-
-instance TH.Lift Delegation where
-  lift (Delegation pat repl) = [| Delegation pat repl |]
-#endif
-
 {-------------------------------------------------------------------------------
   JSON
 -------------------------------------------------------------------------------}
@@ -346,9 +323,8 @@
             )
 
 _ex2 :: Maybe String
-_ex2 = matchDelegation del "A/x/y/z.foo"
-  where
-    Right del = parseDelegation "A/*/*/*.foo" "B/*/C/*/*.bar"
+_ex2 = either undefined (`matchDelegation` "A/x/y/z.foo")
+  (parseDelegation "A/*/*/*.foo" "B/*/C/*/*.bar")
 
 _ex3 :: Either String Delegation
 _ex3 = parseDelegation "foo" "*/bar"
diff --git a/src/Hackage/Security/TUF/Root.hs b/src/Hackage/Security/TUF/Root.hs
--- a/src/Hackage/Security/TUF/Root.hs
+++ b/src/Hackage/Security/TUF/Root.hs
@@ -6,7 +6,7 @@
   , RoleSpec(..)
   ) where
 
-import MyPrelude
+import Prelude
 import Hackage.Security.JSON
 import Hackage.Security.Key
 import Hackage.Security.Key.Env (KeyEnv)
diff --git a/src/Hackage/Security/TUF/Signed.hs b/src/Hackage/Security/TUF/Signed.hs
--- a/src/Hackage/Security/TUF/Signed.hs
+++ b/src/Hackage/Security/TUF/Signed.hs
@@ -27,7 +27,7 @@
   , toPreSignatures
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Monad
 import Data.Functor.Identity
 import qualified Data.ByteString      as BS
diff --git a/src/Hackage/Security/TUF/Snapshot.hs b/src/Hackage/Security/TUF/Snapshot.hs
--- a/src/Hackage/Security/TUF/Snapshot.hs
+++ b/src/Hackage/Security/TUF/Snapshot.hs
@@ -3,7 +3,7 @@
     Snapshot(..)
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Monad.Except
 import Control.Monad.Reader
 
diff --git a/src/Hackage/Security/TUF/Targets.hs b/src/Hackage/Security/TUF/Targets.hs
--- a/src/Hackage/Security/TUF/Targets.hs
+++ b/src/Hackage/Security/TUF/Targets.hs
@@ -8,7 +8,7 @@
   , targetsLookup
   ) where
 
-import MyPrelude
+import Prelude
 import Hackage.Security.JSON
 import Hackage.Security.Key
 import Hackage.Security.Key.Env (KeyEnv)
diff --git a/src/Hackage/Security/TUF/Timestamp.hs b/src/Hackage/Security/TUF/Timestamp.hs
--- a/src/Hackage/Security/TUF/Timestamp.hs
+++ b/src/Hackage/Security/TUF/Timestamp.hs
@@ -3,7 +3,7 @@
     Timestamp(..)
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Monad.Except
 import Control.Monad.Reader
 
diff --git a/src/Hackage/Security/Trusted.hs b/src/Hackage/Security/Trusted.hs
--- a/src/Hackage/Security/Trusted.hs
+++ b/src/Hackage/Security/Trusted.hs
@@ -1,7 +1,5 @@
-{-# LANGUAGE CPP #-}
-#if __GLASGOW_HASKELL__ >= 710
 {-# LANGUAGE StaticPointers #-}
-#endif
+
 module Hackage.Security.Trusted (
     module Hackage.Security.Trusted.TCB
     -- * Derived functions
@@ -12,7 +10,7 @@
   , trustedFileInfoEqual
   ) where
 
-import MyPrelude
+import Prelude
 import Data.Function (on)
 import Data.Time
 import Hackage.Security.TUF
diff --git a/src/Hackage/Security/Trusted/TCB.hs b/src/Hackage/Security/Trusted/TCB.hs
--- a/src/Hackage/Security/Trusted/TCB.hs
+++ b/src/Hackage/Security/Trusted/TCB.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 module Hackage.Security.Trusted.TCB (
     -- * Trusted values
     Trusted(DeclareTrusted)
@@ -16,17 +15,11 @@
   , signaturesVerified
   , verifyRole'
   , verifyFingerprints
-#if __GLASGOW_HASKELL__ >= 710
     -- * Re-exports
   , StaticPtr
-#else
-    -- * Fake static pointers
-  , StaticPtr
-  , static
-#endif
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Exception
 import Control.Monad (when, unless)
 import Control.Monad.Except (Except, runExcept, throwError)
@@ -38,18 +31,8 @@
 import Hackage.Security.Util.Pretty
 import qualified Hackage.Security.Util.Lens as Lens
 
-#if __GLASGOW_HASKELL__ >= 710
 import GHC.StaticPtr
-#else
--- Fake static pointers for ghc < 7.10. This means Trusted offers no
--- additional type safety, but that's okay: we can still verify the code
--- with ghc 7.10 and get the additional checks.
-newtype StaticPtr a = StaticPtr { deRefStaticPtr :: a }
 
-static :: a -> StaticPtr a
-static = StaticPtr
-#endif
-
 -- | Trusted values
 --
 -- Trusted values originate in only two ways:
@@ -209,17 +192,10 @@
 
 type VerificationHistory = [Either RootUpdated VerificationError]
 
-#if MIN_VERSION_base(4,8,0)
 deriving instance Show VerificationError
 deriving instance Show RootUpdated
 instance Exception VerificationError where displayException = pretty
 instance Exception RootUpdated where displayException = pretty
-#else
-instance Exception VerificationError
-instance Show VerificationError where show = pretty
-instance Show RootUpdated where show = pretty
-instance Exception RootUpdated
-#endif
 
 indentedLines :: [String] -> String
 indentedLines = unlines . map ("  " ++)
diff --git a/src/Hackage/Security/Util/Base64.hs b/src/Hackage/Security/Util/Base64.hs
--- a/src/Hackage/Security/Util/Base64.hs
+++ b/src/Hackage/Security/Util/Base64.hs
@@ -4,7 +4,7 @@
   , toByteString
   ) where
 
-import MyPrelude
+import Prelude
 import Data.ByteString (ByteString)
 import qualified Data.ByteString.Char8  as C8  -- only called on B64-enc strings
 import qualified Data.ByteString.Base64 as B64
diff --git a/src/Hackage/Security/Util/Checked.hs b/src/Hackage/Security/Util/Checked.hs
--- a/src/Hackage/Security/Util/Checked.hs
+++ b/src/Hackage/Security/Util/Checked.hs
@@ -1,15 +1,9 @@
-{-# LANGUAGE CPP #-}
-{-# OPTIONS_GHC -fno-warn-unused-binds #-}
-#if __GLASGOW_HASKELL__ >= 800
-{-# OPTIONS_GHC -Wno-redundant-constraints #-}
-#endif
-
-#if __GLASGOW_HASKELL__ >= 708
-{-# LANGUAGE RoleAnnotations     #-}
+{-# LANGUAGE DeriveDataTypeable  #-}
 {-# LANGUAGE IncoherentInstances #-}
-#endif
+{-# LANGUAGE RoleAnnotations     #-}
 
-{-# LANGUAGE DeriveDataTypeable#-}
+{-# OPTIONS_GHC -Wno-unused-binds #-}
+{-# OPTIONS_GHC -Wno-redundant-constraints #-}
 
 -- | Checked exceptions
 module Hackage.Security.Util.Checked (
@@ -25,16 +19,12 @@
   , internalError
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Exception (Exception, IOException)
 import qualified Control.Exception as Base
 import Data.Typeable (Typeable)
 
-#if __GLASGOW_HASKELL__ >= 708
 import GHC.Prim (coerce)
-#else
-import Unsafe.Coerce (unsafeCoerce)
-#endif
 
 {-------------------------------------------------------------------------------
   Basic infrastructure
@@ -43,9 +33,7 @@
 -- | Checked exceptions
 class Throws e where
 
-#if __GLASGOW_HASKELL__ >= 708
 type role Throws representational
-#endif
 
 unthrow :: forall a e proxy . proxy e -> (Throws e => a) -> a
 unthrow _ x = unWrap (coerceWrap (Wrap x :: Wrap e a))
@@ -56,22 +44,10 @@
 
 -- | Determine if an exception is asynchronous, based on its type.
 isAsync :: Exception e => e -> Bool
-#if MIN_VERSION_base(4, 7, 0)
 isAsync e =
   case Base.fromException $ Base.toException e of
     Just Base.SomeAsyncException{} -> True
     Nothing -> False
-#else
--- Earlier versions of GHC had no SomeAsyncException. We have to
--- instead make up a list of async exceptions.
-isAsync e =
-  let se = Base.toException e
-   in case () of
-        ()
-          | Just (_ :: Base.AsyncException) <- Base.fromException se -> True
-          | show e == "<<timeout>>" -> True
-          | otherwise -> False
-#endif
 
 -- | 'Base.catch', but immediately rethrows asynchronous exceptions
 -- (as determined by 'isAsync').
@@ -131,11 +107,7 @@
 newtype Wrap e a = Wrap { unWrap :: Throws e => a }
 
 coerceWrap :: Wrap e a -> Wrap (Catch e) a
-#if __GLASGOW_HASKELL__ >= 708
 coerceWrap = coerce
-#else
-coerceWrap = unsafeCoerce
-#endif
 
 data Proxy a = Proxy
 
diff --git a/src/Hackage/Security/Util/Exit.hs b/src/Hackage/Security/Util/Exit.hs
--- a/src/Hackage/Security/Util/Exit.hs
+++ b/src/Hackage/Security/Util/Exit.hs
@@ -1,6 +1,6 @@
 module Hackage.Security.Util.Exit where
 
-import MyPrelude
+import Prelude
 import Control.Monad (liftM)
 import Control.Monad.Except (ExceptT, runExceptT, throwError)
 
diff --git a/src/Hackage/Security/Util/IO.hs b/src/Hackage/Security/Util/IO.hs
--- a/src/Hackage/Security/Util/IO.hs
+++ b/src/Hackage/Security/Util/IO.hs
@@ -9,7 +9,7 @@
   , timedIO
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Concurrent (threadDelay)
 import Control.Exception
 import Data.Time
diff --git a/src/Hackage/Security/Util/JSON.hs b/src/Hackage/Security/Util/JSON.hs
--- a/src/Hackage/Security/Util/JSON.hs
+++ b/src/Hackage/Security/Util/JSON.hs
@@ -1,7 +1,3 @@
-{-# LANGUAGE CPP #-}
-#if __GLASGOW_HASKELL__ < 710
-{-# LANGUAGE OverlappingInstances #-}
-#endif
 -- |
 module Hackage.Security.Util.JSON (
     -- * Type classes
@@ -23,7 +19,7 @@
   , Int54
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Monad (liftM)
 import Data.Maybe (catMaybes)
 import Data.Map (Map)
@@ -32,10 +28,6 @@
 import Network.URI
 import qualified Data.Map as Map
 
-#if !MIN_VERSION_time(1,5,0)
-import System.Locale (defaultTimeLocale)
-#endif
-
 import Hackage.Security.Util.Path
 
 {-------------------------------------------------------------------------------
@@ -120,16 +112,12 @@
   fromJSON val       = expected' "int" val
 
 instance
-#if __GLASGOW_HASKELL__ >= 710
   {-# OVERLAPPABLE #-}
-#endif
     (Monad m, ToJSON m a) => ToJSON m [a] where
   toJSON = liftM JSArray . mapM toJSON
 
 instance
-#if __GLASGOW_HASKELL__ >= 710
   {-# OVERLAPPABLE #-}
-#endif
     (ReportSchemaErrors m, FromJSON m a) => FromJSON m [a] where
   fromJSON (JSArray as) = mapM fromJSON as
   fromJSON val          = expected' "array" val
@@ -143,10 +131,6 @@
     case parseTimeM False defaultTimeLocale "%FT%TZ" str of
       Just time -> return time
       Nothing   -> expected "valid date-time string" (Just str)
-#if !MIN_VERSION_time(1,5,0)
-    where
-      parseTimeM _trim = parseTime
-#endif
 
 instance ( Monad m
          , ToObjectKey m k
diff --git a/src/Hackage/Security/Util/Lens.hs b/src/Hackage/Security/Util/Lens.hs
--- a/src/Hackage/Security/Util/Lens.hs
+++ b/src/Hackage/Security/Util/Lens.hs
@@ -14,7 +14,7 @@
   , set
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Applicative
 import Data.Functor.Identity
 
diff --git a/src/Hackage/Security/Util/Path.hs b/src/Hackage/Security/Util/Path.hs
--- a/src/Hackage/Security/Util/Path.hs
+++ b/src/Hackage/Security/Util/Path.hs
@@ -7,7 +7,6 @@
 --
 -- Note that his module does not import any other modules from Hackage.Security;
 -- everywhere else we use Path instead of FilePath directly.
-{-# LANGUAGE CPP #-}
 module Hackage.Security.Util.Path (
     -- * Paths
     Path(..)
@@ -83,16 +82,12 @@
   , IO.hSeek
   ) where
 
-import MyPrelude
+import Prelude
 import Control.Monad
 import Data.List (isPrefixOf)
 import System.IO (IOMode(..), BufferMode(..), Handle, SeekMode(..))
 import System.IO.Unsafe (unsafeInterleaveIO)
-#if MIN_VERSION_directory(1,2,0)
 import Data.Time (UTCTime)
-#else
-import System.Time (ClockTime)
-#endif
 import qualified Data.ByteString         as BS
 import qualified Data.ByteString.Lazy    as BS.L
 import qualified System.FilePath         as FP.Native
@@ -239,21 +234,7 @@
   toAbsoluteFilePath :: Path root -> IO FilePath
 
 instance FsRoot Relative where
-    toAbsoluteFilePath p = go (unPathNative p)
-      where
-        go :: FilePath -> IO FilePath
-#if MIN_VERSION_directory(1,2,2)
-        go = Dir.makeAbsolute
-#else
-        -- copied implementation from the directory package
-        go = (FP.Native.normalise <$>) . absolutize
-        absolutize path -- avoid the call to `getCurrentDirectory` if we can
-          | FP.Native.isRelative path
-                      = (FP.Native.</> path)
-                      . FP.Native.addTrailingPathSeparator <$>
-                        Dir.getCurrentDirectory
-          | otherwise = return path
-#endif
+    toAbsoluteFilePath p = Dir.makeAbsolute (unPathNative p)
 
 instance FsRoot Absolute where
     toAbsoluteFilePath = return . unPathNative
@@ -371,11 +352,7 @@
     filePath <- toAbsoluteFilePath path
     Dir.doesDirectoryExist filePath
 
-#if MIN_VERSION_directory(1,2,0)
 getModificationTime :: FsRoot root => Path root -> IO UTCTime
-#else
-getModificationTime :: FsRoot root => Path root -> IO ClockTime
-#endif
 getModificationTime path = do
     filePath <- toAbsoluteFilePath path
     Dir.getModificationTime filePath
diff --git a/src/Hackage/Security/Util/Pretty.hs b/src/Hackage/Security/Util/Pretty.hs
--- a/src/Hackage/Security/Util/Pretty.hs
+++ b/src/Hackage/Security/Util/Pretty.hs
@@ -3,7 +3,7 @@
     Pretty(..)
   ) where
 
-import MyPrelude
+import Prelude
 
 -- | Produce a human-readable string
 class Pretty a where
diff --git a/src/Hackage/Security/Util/Some.hs b/src/Hackage/Security/Util/Some.hs
--- a/src/Hackage/Security/Util/Some.hs
+++ b/src/Hackage/Security/Util/Some.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 -- | Hiding existentials
 module Hackage.Security.Util.Some (
     Some(..)
@@ -13,30 +12,17 @@
   , SomePretty(..)
     -- ** Type checking
   , typecheckSome
-#if !MIN_VERSION_base(4,7,0)
-    -- ** Compatibility with base < 4.7
-  , tyConSome
-#endif
   ) where
 
-import MyPrelude
-#if MIN_VERSION_base(4,7,0)
+import Prelude
 import Data.Typeable (Typeable)
-#else
-import qualified Data.Typeable as Typeable
-#endif
 
 import Hackage.Security.Util.TypedEmbedded
 import Hackage.Security.Util.Pretty
 
 data Some f = forall a. Some (f a)
 
-#if MIN_VERSION_base(4,7,0)
 deriving instance Typeable Some
-#else
-tyConSome :: Typeable.TyCon
-tyConSome = Typeable.mkTyCon3 "hackage-security" "Hackage.Security.Util.Some" "Some"
-#endif
 
 {-------------------------------------------------------------------------------
   Equality on Some types
diff --git a/src/Hackage/Security/Util/Stack.hs b/src/Hackage/Security/Util/Stack.hs
--- a/src/Hackage/Security/Util/Stack.hs
+++ b/src/Hackage/Security/Util/Stack.hs
@@ -3,7 +3,7 @@
     (:-)(..)
   ) where
 
-import MyPrelude
+import Prelude
 
 data h :- t = h :- t
   deriving (Eq, Show)
diff --git a/src/Hackage/Security/Util/TypedEmbedded.hs b/src/Hackage/Security/Util/TypedEmbedded.hs
--- a/src/Hackage/Security/Util/TypedEmbedded.hs
+++ b/src/Hackage/Security/Util/TypedEmbedded.hs
@@ -7,7 +7,8 @@
   , AsType(..)
   ) where
 
-import MyPrelude
+import Prelude
+import Data.Kind (Type)
 
 -- | Type equality proofs
 --
@@ -16,7 +17,7 @@
 data a :=: b where
   Refl :: a :=: a
 
-type family TypeOf (f :: * -> *) :: * -> *
+type family TypeOf (f :: Type -> Type) :: Type -> Type
 
 -- | Equality check that gives us a type-level equality proof.
 class Unify f where
diff --git a/src/MyPrelude.hs b/src/MyPrelude.hs
deleted file mode 100644
--- a/src/MyPrelude.hs
+++ /dev/null
@@ -1,31 +0,0 @@
--- | Smooth over differences between various ghc versions by making older
--- preludes look like 4.8.0
-{-# LANGUAGE CPP #-}
-module MyPrelude (
-    module P
-#if !MIN_VERSION_base(4,8,0)
-  , Applicative(..)
-  , Monoid(..)
-  , (<$>)
-  , (<$)
-  , Traversable(traverse)
-  , displayException
-#endif
-  ) where
-
-#if MIN_VERSION_base(4,8,0)
-import Prelude as P
-#else
-#if MIN_VERSION_base(4,6,0)
-import Prelude as P
-#else
-import Prelude as P hiding (catch)
-#endif
-import Control.Applicative
-import Control.Exception (Exception)
-import Data.Monoid
-import Data.Traversable (Traversable(traverse))
-
-displayException :: Exception e => e -> String
-displayException = show
-#endif
diff --git a/src/Text/JSON/Canonical.hs b/src/Text/JSON/Canonical.hs
--- a/src/Text/JSON/Canonical.hs
+++ b/src/Text/JSON/Canonical.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE CPP #-}
---------------------------------------------------------------------
 -- |
 -- Module    : Text.JSON.Parsec
 -- Copyright : (c) Galois, Inc. 2007-2009, Duncan Coutts 2015
@@ -30,21 +28,15 @@
   , prettyCanonicalJSON
   ) where
 
-import MyPrelude
+import Prelude
 import Text.ParserCombinators.Parsec
          ( CharParser, (<|>), (<?>), many, between, sepBy
          , satisfy, char, string, digit, spaces
          , parse )
 import Text.PrettyPrint hiding (char)
 import qualified Text.PrettyPrint as Doc
-#if !(MIN_VERSION_base(4,7,0))
-import Control.Applicative ((<$>), (<$), pure, (<*>), (<*), (*>))
-#endif
 import Control.Arrow (first)
-import Data.Bits (Bits)
-#if MIN_VERSION_base(4,7,0)
-import Data.Bits (FiniteBits)
-#endif
+import Data.Bits (Bits, FiniteBits)
 import Data.Char (isDigit, digitToInt)
 import Data.Data (Data)
 import Data.Function (on)
@@ -83,9 +75,7 @@
            , Ord
            , Real
            , Ix
-#if MIN_VERSION_base(4,7,0)
            , FiniteBits
-#endif
            , Bits
            , Storable
            , PrintfArg
@@ -353,4 +343,3 @@
     go []     = []
     go [y]    = [p <+> y, r]
     go (y:ys) = (p <+> y) : go ys
-
diff --git a/tests/TestSuite.hs b/tests/TestSuite.hs
--- a/tests/TestSuite.hs
+++ b/tests/TestSuite.hs
@@ -238,7 +238,7 @@
     length (directoryEntries dir1) @?= 0
 
     now <- getCurrentTime
-    inMemRepoSetIndex inMemRepo now [testEntry1]
+    inMemRepoSetIndex inMemRepo now testEntries1
 
     assertEqual "B" HasUpdates =<< checkForUpdates repo =<< checkExpiry
     dir2 <- getDirectory repo
@@ -264,9 +264,9 @@
              _        -> fail "unexpected index entry content"
          _ -> fail "unexpected index path"
 
-    testEntry1 = Tar.fileEntry path testEntrycontent
-      where
-        Right path = Tar.toTarPath False "foo/preferred-versions"
+    testEntries1 :: [Tar.GenEntry Tar.TarPath linkTarget]
+    testEntries1 = either (const []) (pure . (`Tar.fileEntry` testEntrycontent))
+        (Tar.toTarPath False "foo/preferred-versions")
     testEntrycontent   = BS.pack "foo >= 1"
     testEntryIndexFile = IndexPkgPrefs (mkPackageName "foo")
 
diff --git a/tests/TestSuite/InMemRepo.hs b/tests/TestSuite/InMemRepo.hs
--- a/tests/TestSuite/InMemRepo.hs
+++ b/tests/TestSuite/InMemRepo.hs
@@ -8,6 +8,7 @@
 
 -- stdlib
 import Control.Exception
+import Data.Kind (Type)
 import Data.Time
 import qualified Codec.Archive.Tar      as Tar
 import qualified Codec.Compression.GZip as GZip
@@ -33,7 +34,7 @@
   "Files" from the in-memory repository
 -------------------------------------------------------------------------------}
 
-data InMemFile :: * -> * where
+data InMemFile :: Type -> Type where
     InMemMetadata :: ToJSON WriteJSON a => RepoLayout -> a -> InMemFile Metadata
     InMemBinary   :: BS.L.ByteString -> InMemFile Binary
 
diff --git a/tests/TestSuite/JSON.hs b/tests/TestSuite/JSON.hs
--- a/tests/TestSuite/JSON.hs
+++ b/tests/TestSuite/JSON.hs
@@ -11,7 +11,6 @@
 import Data.Int
 import Data.List (sortBy, nubBy)
 import Data.Function (on)
-import Control.Applicative
 import qualified Data.ByteString.Lazy.Char8 as BS
 import Test.QuickCheck