diff --git a/butcher.cabal b/butcher.cabal
index e41f40b..5d49b0b 100644
--- a/butcher.cabal
+++ b/butcher.cabal
@@ -53,7 +53,7 @@ library
                        UI.Butcher.Internal.Pretty
                        UI.Butcher.Internal.Interactive
   build-depends:
-    { base >=4.11 && <4.15
+    { base >=4.11 && <4.16
     , free < 5.2
     , unsafe < 0.1
     , microlens <0.5
diff --git a/seaaye.nix b/seaaye.nix
index b654f29..2d50672 100644
--- a/seaaye.nix
+++ b/seaaye.nix
@@ -19,6 +19,11 @@
       index-state = "2022-07-01T00:00:00Z";
       ghc-ver = "ghc8107";
     };
+    hackage-9-00 = {
+      resolver = "hackage";
+      index-state = "2022-07-01T00:00:00Z";
+      ghc-ver = "ghc902";
+    };
     stackage-8-06 = {
       resolver = "stackage";
       stackFile = "stack-8-6.yaml";
@@ -34,6 +39,11 @@
       stackFile = "stack-8-10.yaml";
       ghc-ver = "ghc8107";
     };
+    stackage-9-00 = {
+      resolver = "stackage";
+      stackFile = "stack-9-0.yaml";
+      ghc-ver = "ghc902";
+    };
   };
   module-flags = [
     # N.B.: There are haskell-nix module options. See the haskell-nix docs
diff --git a/stack-9-0.yaml b/stack-9-0.yaml
new file mode 100644
index 0000000..6b1e11f
--- /dev/null
+++ b/stack-9-0.yaml
@@ -0,0 +1,30 @@
+resolver: lts-19.33
+
+packages:
+- .
+
+extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=2.1"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor