diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,14 +1,32 @@
 # Revision history for env-guard
 
-## 0.2 -- 2022-07-02
+All notable changes to this project will be documented in this file.
 
-* Rename `guardExpected` functions to `guardEquals` to better match ExpectEnv type.
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to the [Haskell Package Versioning Policy](https://pvp.haskell.org/).
 
-## 0.1.1 -- 2022-07-01
+## [0.2.1] -- 2025-07-17
+### Changed
+* Fixed `Show ExpectEnv` instance constructor name.
+* Explicitly Re-export `ExpectEnv` data constructors from
+  `System.Environment.Guard`.
+* Doctests use cabal external command, hence no longer part of test suite.
+  Therefore `--enable-tests` will no longer incur a GHC dependency.
 
+## [0.2] -- 2022-07-02
+### Changed
+* Rename `guardExpected` functions to `guardEquals` to better match ExpectEnv type.
+
+## [0.1.1] -- 2022-07-01
+### Added
 * Add higher-level `withGuard` combinator.
 * Add "OrElse" pattern.
 
-## 0.1 -- 2022-06-29
+## [0.1] -- 2022-06-29
 
 * First version. Released on an unsuspecting world.
+
+[0.2.1]: https://github.com/tbidne/env-guard/compare/0.2..0.2.1
+[0.2]: https://github.com/tbidne/env-guard/compare/0.1.1..0.2
+[0.1.1]: https://github.com/tbidne/env-guard/compare/0.1..0.1.1
+[0.1]: https://github.com/tbidne/env-guard/releases/tag/0.1
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2022 Thomas Bidne
+Copyright (c) 2022-2025 Thomas Bidne
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -3,14 +3,65 @@
 # env-guard
 
 [![Hackage](https://img.shields.io/hackage/v/env-guard)](https://hackage.haskell.org/package/env-guard)
+[![ci](http://img.shields.io/github/actions/workflow/status/tbidne/env-guard/ci.yaml?branch=main)](https://github.com/tbidne/env-guard/actions/workflows/ci.yaml)
 [![MIT](https://img.shields.io/github/license/tbidne/env-guard?color=blue)](https://opensource.org/licenses/MIT)
 
-[![nix](https://img.shields.io/github/workflow/status/tbidne/env-guard/nix/main?label=nix%209.2&&logo=nixos&logoColor=85c5e7&labelColor=2f353c)](https://github.com/tbidne/env-guard/actions/workflows/nix_ci.yaml)
-[![stack](https://img.shields.io/github/workflow/status/tbidne/env-guard/stack/main?label=stack%2019&logoColor=white&labelColor=2f353c)](https://github.com/tbidne/env-guard/actions/workflows/stack_ci.yaml)
-[![style](https://img.shields.io/github/workflow/status/tbidne/env-guard/style/main?label=style&logoColor=white&labelColor=2f353c)](https://github.com/tbidne/env-guard/actions/workflows/style_ci.yaml)
+</div>
 
-[![8.10](https://img.shields.io/github/workflow/status/tbidne/env-guard/8.10/main?label=8.10&logo=haskell&logoColor=904d8c&labelColor=2f353c)](https://github.com/tbidne/env-guard/actions/workflows/ghc_8-10.yaml)
-[![9.0](https://img.shields.io/github/workflow/status/tbidne/env-guard/9.0/main?label=9.0&logo=haskell&logoColor=904d8c&labelColor=2f353c)](https://github.com/tbidne/env-guard/actions/workflows/ghc_9-0.yaml)
-[![9.2](https://img.shields.io/github/workflow/status/tbidne/env-guard/9.2/main?label=9.2&logo=haskell&logoColor=904d8c&labelColor=2f353c)](https://github.com/tbidne/env-guard/actions/workflows/ghc_9-2.yaml)
+# Introduction
 
-</div>
+This package is used to guard `IO` actions behind an environment variable.
+
+# Examples
+
+## Simple
+
+```haskell
+guardSet :: String -> IO a -> IO (Maybe a)
+
+-- Run function if env var AppEnv is set (to anything).
+guardSet "AppEnv" runProd
+```
+
+```haskell
+guardEquals :: String -> String -> IO a -> IO (Maybe a)
+
+-- Run function if env var AppEnv is set to "prod" (case-insensitive).
+guardEquals "AppEnv" "prod" runProd
+```
+
+```haskell
+guardPredicate :: String -> (String -> Bool) -> IO a -> IO (Maybe a)
+
+-- Run function if env var AppEnv's value satisfies the predicate.
+guardPredicate "AppEnv" (\s -> s == "staging" || s == "dev") runTests
+```
+
+## Higher-Level Combinators
+
+```haskell
+-- withGuard uses the 'ExpectEnv' type to determine which of the above three
+-- functions to call.
+withGuard :: String -> ExpectEnv -> IO a -> IO (Maybe a)
+
+-- equivalent to 'guardSet "BUILD_DOCS" buildDocs'.
+withGuard "BUILD_DOCS" ExpectEnvSet buildDocs
+
+-- equivalent to 'guardEquals "BUILD_DOCS" "true" buildDocs'.
+withGuard "BUILD_DOCS" (ExpectEnvEquals "true") buildDocs
+```
+
+```haskell
+-- guardOrElse runs one of two IO actions, depending on the success of the env
+-- variable lookup.
+guardOrElse :: String -> ExpectEnv -> IO a -> IO e -> IO (Either e a)
+
+-- Runs runA if DO_A is set; otherwise runs runB.
+guardOrElse "DO_A" ExpectEnvSet runA runB
+
+-- guardOrElse' specialized to the same type.
+guardOrElse' :: String -> ExpectEnv -> IO a -> IO a -> IO a
+
+-- Runs runTests if RUN_TESTS is set; otherwise prints a message.
+guardOrElse' "RUN_TESTS" ExpectEnvSet runTests (putStrLn "*** Tests Disabled ***")
+```
diff --git a/env-guard.cabal b/env-guard.cabal
--- a/env-guard.cabal
+++ b/env-guard.cabal
@@ -1,10 +1,19 @@
 cabal-version:      2.4
 name:               env-guard
-version:            0.2
+version:            0.2.1
 license:            MIT
 license-file:       LICENSE
-tested-with:        GHC ==8.10.7 || ==9.0.2 || ==9.2.3
-copyright:          2022 Thomas Bidne
+tested-with:
+  GHC ==8.10.7
+   || ==9.0.2
+   || ==9.2.8
+   || ==9.4.8
+   || ==9.6.6
+   || ==9.8.4
+   || ==9.10.2
+   || ==9.12.2
+
+copyright:          2022-2025 Thomas Bidne
 author:             Thomas Bidne
 maintainer:         tbidne@protonmail.com
 homepage:           https://github.com/tbidne/env-guard/
@@ -18,9 +27,8 @@
   result.
 
 category:           System, Environment
-extra-source-files:
-  CHANGELOG.md
-  README.md
+extra-source-files: README.md
+extra-doc-files:    CHANGELOG.md
 
 source-repository head
   type:     git
@@ -31,16 +39,6 @@
     System.Environment.Guard
     System.Environment.Guard.Lifted
 
-  build-depends:    base >=4.14.0.0 && <4.17
+  build-depends:    base >=4.14.0.0 && <4.22
   hs-source-dirs:   src
-  default-language: Haskell2010
-
-test-suite doctest
-  type:             exitcode-stdio-1.0
-  main-is:          Main.hs
-  build-depends:
-    , base
-    , doctest  >=0.16.3 && <0.21
-
-  hs-source-dirs:   test/doctest
   default-language: Haskell2010
diff --git a/src/System/Environment/Guard.hs b/src/System/Environment/Guard.hs
--- a/src/System/Environment/Guard.hs
+++ b/src/System/Environment/Guard.hs
@@ -28,7 +28,13 @@
   )
 where
 
-import System.Environment.Guard.Lifted (ExpectEnv)
+import System.Environment.Guard.Lifted
+  ( ExpectEnv
+      ( ExpectEnvEquals,
+        ExpectEnvPredicate,
+        ExpectEnvSet
+      ),
+  )
 import System.Environment.Guard.Lifted qualified as Lifted
 
 -- $setup
diff --git a/src/System/Environment/Guard/Lifted.hs b/src/System/Environment/Guard/Lifted.hs
--- a/src/System/Environment/Guard/Lifted.hs
+++ b/src/System/Environment/Guard/Lifted.hs
@@ -28,8 +28,9 @@
 where
 
 import Control.Monad (void)
-import Control.Monad.IO.Class (MonadIO (..))
+import Control.Monad.IO.Class (MonadIO (liftIO))
 import Data.Char (toLower)
+import GHC.Show (appPrec)
 import System.Environment (lookupEnv)
 
 -- $setup
@@ -61,12 +62,12 @@
   showsPrec _ ExpectEnvSet = showString "ExpectEnvSet"
   showsPrec i (ExpectEnvEquals s) =
     showParen
-      (i >= 11)
-      (showString "ExpectEnvEquals " . showsPrec 11 s)
+      (i >= appPrec)
+      (showString "ExpectEnvEquals " . showsPrec appPrec s)
   showsPrec i (ExpectEnvPredicate _) =
     showParen
-      (i >= 11)
-      (showString "ExpectEnvEquals " . showString "_")
+      (i >= appPrec)
+      (showString "ExpectEnvPredicate " . showString "<function>")
 
 -- | Guards an action behind an environment variable according to
 -- the given expectation.
@@ -81,7 +82,7 @@
 -- Just ()
 --
 -- @since 0.1.1
-withGuard :: MonadIO m => String -> ExpectEnv -> m a -> m (Maybe a)
+withGuard :: (MonadIO m) => String -> ExpectEnv -> m a -> m (Maybe a)
 withGuard var expect m =
   case expect of
     ExpectEnvSet -> guardSet var m
@@ -91,7 +92,7 @@
 -- | Variant of 'withGuard' that ignores the return value.
 --
 -- @since 0.1.1
-withGuard_ :: MonadIO m => String -> ExpectEnv -> m a -> m ()
+withGuard_ :: (MonadIO m) => String -> ExpectEnv -> m a -> m ()
 withGuard_ var expect = void . withGuard var expect
 
 -- | @guardOrElse var expect m1 m2@ is equivalent to
@@ -107,7 +108,7 @@
 --
 -- @since 0.1.1
 guardOrElse ::
-  MonadIO m =>
+  (MonadIO m) =>
   -- | The environment variable.
   String ->
   -- | The expectation.
@@ -144,7 +145,7 @@
 --
 -- @since 0.1.1
 guardOrElse' ::
-  MonadIO m =>
+  (MonadIO m) =>
   -- | The environment variable.
   String ->
   -- | The expectation.
@@ -176,13 +177,13 @@
 -- Just True
 --
 -- @since 0.1
-guardSet :: MonadIO m => String -> m a -> m (Maybe a)
+guardSet :: (MonadIO m) => String -> m a -> m (Maybe a)
 guardSet var = guardPredicate var (const True)
 
 -- | Variant of 'guardSet' that ignores the return value.
 --
 -- @since 0.1
-guardSet_ :: MonadIO m => String -> m a -> m ()
+guardSet_ :: (MonadIO m) => String -> m a -> m ()
 guardSet_ var = void . guardSet var
 
 -- | @'guardEquals' var expected io@ runs @io@ iff
@@ -209,19 +210,19 @@
 -- Just True
 --
 -- @since 0.2
-guardEquals :: MonadIO m => String -> String -> m a -> m (Maybe a)
+guardEquals :: (MonadIO m) => String -> String -> m a -> m (Maybe a)
 guardEquals var expected = guardPredicate var (eqCaseInsensitive expected)
 
 -- | Variant of 'guardEquals_' that ignores the return value.
 --
 -- @since 0.2
-guardEquals_ :: MonadIO m => String -> String -> m a -> m ()
+guardEquals_ :: (MonadIO m) => String -> String -> m a -> m ()
 guardEquals_ var expected = void . guardEquals var expected
 
 -- | Variant of 'guardPredicate' that ignores the return value.
 --
 -- @since 0.1
-guardPredicate_ :: MonadIO m => String -> (String -> Bool) -> m a -> m ()
+guardPredicate_ :: (MonadIO m) => String -> (String -> Bool) -> m a -> m ()
 guardPredicate_ var p = void . guardPredicate var p
 
 -- | This is the most general way to check an environment variable.
@@ -245,7 +246,7 @@
 -- Just True
 --
 -- @since 0.1
-guardPredicate :: MonadIO m => String -> (String -> Bool) -> m a -> m (Maybe a)
+guardPredicate :: (MonadIO m) => String -> (String -> Bool) -> m a -> m (Maybe a)
 guardPredicate var p io =
   liftIO (lookupEnv var)
     >>= \case
diff --git a/test/doctest/Main.hs b/test/doctest/Main.hs
deleted file mode 100644
--- a/test/doctest/Main.hs
+++ /dev/null
@@ -1,21 +0,0 @@
-module Main (main) where
-
-import System.Environment (lookupEnv)
-import Test.DocTest (doctest)
-import Prelude
-
-main :: IO ()
-main = do
-  shouldRun <- lookupEnv "RUN_DOCTEST"
-  case shouldRun of
-    Just _ -> doctest args
-    _ -> putStrLn "*** Doctests Disabled ***"
-  where
-    args = files
-
-files :: [String]
-files =
-  [ "-isrc",
-    "src/System/Environment/Guard.hs",
-    "src/System/Environment/Guard/Lifted.hs"
-  ]