diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
index 8dbd5f3..9711710 100644
--- a/.github/workflows/haskell-ci.yml
+++ b/.github/workflows/haskell-ci.yml
@@ -26,6 +26,8 @@ jobs:
     strategy:
       matrix:
         include:
+          - compiler: ghc-9.0.1
+            allow-failure: false
           - compiler: ghc-8.10.4
             allow-failure: false
           - compiler: ghc-8.8.4
diff --git a/.github/workflows/stack.yml b/.github/workflows/stack.yml
index 3f65ff7..008edf2 100644
--- a/.github/workflows/stack.yml
+++ b/.github/workflows/stack.yml
@@ -6,13 +6,16 @@ on:
 
 jobs:
   build:
-    name: CI
-    runs-on: ${{ matrix.os }}
+    name: Stack CI - Linux - ${{ matrix.resolver }}
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest]
-        resolver: [lts-16, lts-15, lts-14, lts-12]
+        include:
+          - resolver: lts-12
+          - resolver: lts-14
+          - resolver: lts-16
+          - resolver: lts-17
 
     steps:
       - name: Clone project
diff --git a/xmonad.cabal b/xmonad.cabal
index 1e098f4..a4fd031 100644
--- a/xmonad.cabal
+++ b/xmonad.cabal
@@ -27,7 +27,7 @@ author:             Spencer Janssen, Don Stewart, Adam Vogt, David Roundy, Jason
                     Ondřej Súkup, Paul Hebble, Shachaf Ben-Kiki, Siim Põder, Tim McIver,
                     Trevor Elliott, Wouter Swierstra, Conrad Irwin, Tim Thelion
 maintainer:         xmonad@haskell.org
-tested-with:        GHC == 8.4.4 || == 8.6.5 || == 8.8.4 || == 8.10.3
+tested-with:        GHC == 8.4.4 || == 8.6.5 || == 8.8.4 || == 8.10.4 || == 9.0.1
 category:           System
 homepage:           http://xmonad.org
 bug-reports:        https://github.com/xmonad/xmonad/issues