diff --git a/CHANGES.md b/CHANGES.md
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,7 @@
+## [v0.4.1.1](https://github.com/diagrams/diagrams-haddock/tree/v0.4.1.1) (2021-11-09)
+
+- Allow `Cabal-3.6`
+
 ## [v0.4.1](https://github.com/diagrams/diagrams-haddock/tree/v0.4.1) (2021-08-12)
 
 - Allow `base-4.15`, `bytestring-0.11`, `strict-0.4`, `lens-5.0`,
diff --git a/diagrams-haddock.cabal b/diagrams-haddock.cabal
--- a/diagrams-haddock.cabal
+++ b/diagrams-haddock.cabal
@@ -1,5 +1,5 @@
 name:                diagrams-haddock
-version:             0.4.1
+version:             0.4.1.1
 synopsis:            Preprocessor for embedding diagrams in Haddock documentation
 description:         diagrams-haddock is a tool for compiling embedded inline
                      diagrams code in Haddock documentation, for an
@@ -15,7 +15,7 @@
                      diagrams-haddock, see the diagrams-contrib
                      package
                      (<http://hackage.haskell.org/package/diagrams%2Dcontrib>).
-homepage:            http://projects.haskell.org/diagrams/
+homepage:            https://diagrams.github.io/
 license:             BSD3
 license-file:        LICENSE
 author:              Brent Yorgey
@@ -69,7 +69,7 @@
                        filepath,
                        diagrams-haddock,
                        cmdargs >= 0.8 && < 0.11,
-                       Cabal >= 1.14 && < 3.5,
+                       Cabal >= 2.2 && < 3.7,
                        cpphs >= 1.15
   hs-source-dirs:      tools
   default-language:    Haskell2010
diff --git a/tools/diagrams-haddock.hs b/tools/diagrams-haddock.hs
--- a/tools/diagrams-haddock.hs
+++ b/tools/diagrams-haddock.hs
@@ -17,49 +17,18 @@
 import           Distribution.Simple.LocalBuildInfo (localPkgDescr)
 import           Distribution.Simple.Utils          (cabalVersion)
 
+#if MIN_VERSION_Cabal(3,6,0)
+import           Distribution.Utils.Path            (getSymbolicPath)
+#endif
+
 import           Language.Preprocessor.Cpphs
 
 import           Paths_diagrams_haddock             (version)
 
-------------------------------------------------------------
--- This is officially an awful mess.
---
--- In Cabal < 2.0, it used the Version type from Data.Version.
---
--- As of Cabal 2.0, Cabal switched to its own Version type in
--- Distribution.Version, and re-exported a 'showVersion' function.
---
--- As of Cabal 2.2, showVersion became deprecated and a 'prettyShow'
--- function was added;  Version moved to Distribution.Types.Version.
---
--- We need to show both Cabal versions and Data.Version
--- versions, hence the CPP mess below.
-
--- 1. We definitely need Data.Version. Import it qualified.
 import qualified Data.Version                       as V
-
--- 2. Import the proper 'Version' type to refer to Cabal versions, and
--- the proper function for showing it.
-#if MIN_VERSION_Cabal(2,2,0)
 import           Distribution.Types.Version         (Version)
 import           Distribution.Pretty                (prettyShow)
-#elif MIN_VERSION_Cabal(2,0,0)
-import           Distribution.Version               (Version)
-import qualified Distribution.Version               as DV
-#else
-import           Data.Version                       (Version)
-#endif
 
--- 3. Define a function for showing Cabal versions.
-showCabalVersion :: Version -> String
-#if   MIN_VERSION_Cabal(2,2,0)
-showCabalVersion = prettyShow
-#elif MIN_VERSION_Cabal(2,0,0)
-showCabalVersion = DV.showVersion
-#else
-showCabalVersion = V.showVersion
-#endif
-
 ------------------------------------------------------------
 ------------------------------------------------------------
 
@@ -119,7 +88,7 @@
   &= program "diagrams-haddock"
   &= summary (unlines
        [ "diagrams-haddock v" ++ V.showVersion version ++ ", (c) 2013-2016 diagrams-haddock team (see LICENSE)"
-       , "compiled using version " ++ showCabalVersion cabalVersion ++ " of the Cabal library"
+       , "compiled using version " ++ prettyShow cabalVersion ++ " of the Cabal library"
        , ""
        , "Compile inline diagrams code in Haddock documentation."
        , ""
@@ -175,7 +144,7 @@
       , "Either it does not exist or it is in the wrong format."
       , "* You may need to run 'cabal configure' first."
       , "* Make sure that the version of Cabal used to compile"
-      , "  diagrams-haddock (" ++ showCabalVersion cabalVersion ++ ") matches the version used"
+      , "  diagrams-haddock (" ++ prettyShow cabalVersion ++ ") matches the version used"
       , "  by the cabal tool."
       , "* Use the -d option if you want diagrams-haddock to look in"
       , "  a different dist directory."
@@ -186,19 +155,21 @@
         Nothing -> return ()
         Just lib -> do
           let buildInfo = P.libBuildInfo lib
+#if MIN_VERSION_Cabal(3,6,0)
+              srcDirs   = map getSymbolicPath (P.hsSourceDirs buildInfo)
+#else
               srcDirs   = P.hsSourceDirs buildInfo
+#endif
               incls     = P.includeDirs buildInfo
               defns     = P.cppOptions buildInfo
               opts' = opts
                     { includeDirs = includeDirs opts ++ incls
                     }
               cabalDefines = parseCabalDefines defns
-          mapM_ (tryProcessFile opts' cabalDefines dir srcDirs) . map toFilePath . P.exposedModules $ lib
+          mapM_ (tryProcessFile opts' cabalDefines dir srcDirs . toFilePath) . P.exposedModules $ lib
 
 getHsenv :: IO (Maybe String)
-getHsenv = do
-  env <- getEnvironment
-  return $ lookup "HSENV_NAME" env
+getHsenv = lookup "HSENV_NAME" <$> getEnvironment
 
 -- | Use @cpphs@'s options parser to handle the options from cabal.
 parseCabalDefines :: [String] -> [(String,String)]