diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8b444ce..50e6fa1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -31,7 +31,10 @@ jobs:
           - '9.6.6'
           - '9.8.4'
           - '9.10.1'
+          - '9.12.1'
         exclude:
+          - os: macOS-latest
+            ghc: 9.10.1
           - os: macOS-latest
             ghc: 9.8.4
           - os: macOS-latest
@@ -53,6 +56,8 @@ jobs:
           - os: macOS-latest
             ghc: 8.2.2
 
+          - os: windows-latest
+            ghc: 9.10.1
           - os: windows-latest
             ghc: 9.8.4
           - os: windows-latest
diff --git a/co-log-core.cabal b/co-log-core.cabal
index 3ba0115..2b5b5a5 100644
--- a/co-log-core.cabal
+++ b/co-log-core.cabal
@@ -50,7 +50,7 @@ source-repository head
   location:            https://github.com/co-log/co-log-core.git
 
 common common-options
-  build-depends:       base >= 4.10.1.0 && < 4.21
+  build-depends:       base >= 4.10.1.0 && < 4.22
 
   ghc-options:         -Wall
                        -Wcompat
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..63f64c9
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,6 @@
+with (import <nixpkgs> {});
+mkShell {
+  buildInputs = [
+    gmp
+  ];
+}