diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index b8f4f2e..30d68b0 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -9,9 +9,9 @@ jobs:
       - uses: haskell-actions/setup@v2
         id: haskell-setup
         with:
-          ghc-version: "8.8.3"
+          ghc-version: "9.8.4"
           enable-stack: true
-          stack-version: "2.5.1"
+          stack-version: "3.11.1"
       - name: Restore caches
         uses: actions/cache@v4
         with:
@@ -19,9 +19,11 @@ jobs:
             ${{steps.haskell-setup.outputs.stack-path}}
             ~/.stack
             ./.stack-work/
-          key: ${{ runner.os }}-${{ hashFiles('**/package.yaml') }}-${{ hashFiles('**/onix.cabal') }}-${{ hashFiles('**/stack.yaml.lock') }}
+          key: ${{ runner.os }}-ghc9.8.4-stack3.11.1-${{ hashFiles('**/package.yaml') }}-${{ hashFiles('**/onix.cabal') }}-${{ hashFiles('**/stack.yaml.lock') }}
+          # Scoped to the toolchain: a bare ${{ runner.os }}- prefix would happily
+          # restore a GHC 8.8.3 store into a 9.8.4 build.
           restore-keys: |
-            ${{ runner.os }}-
+            ${{ runner.os }}-ghc9.8.4-stack3.11.1-
       - run: make test
   e2e:
     name: Test e2e
diff --git a/onix.cabal b/onix.cabal
index 373a58a..f3c8ce6 100644
--- a/onix.cabal
+++ b/onix.cabal
@@ -4,7 +4,7 @@ cabal-version: 1.12
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: ccd13791926f8c74575d5f17648a17adbbe0740ce44707823a93b20ae5f7605c
+-- hash: 07b4003dd4819b94016dc0a6629b5b634c96677c275eb19e5e97c2a6ac30ffd5
 
 name:           onix
 version:        0.1.0.0
@@ -42,19 +42,19 @@ library
   ghc-options: -Wall -fwarn-incomplete-patterns -fwarn-incomplete-uni-patterns
   build-depends:
       base >=4.7 && <5
-    , bytestring ==0.10.10.1
-    , containers ==0.6.2.1
-    , filepath ==1.4.2.1
-    , http-client ==0.6.4.1
-    , http-client-tls ==0.3.5.3
-    , mustache ==2.3.1
-    , network-uri ==2.6.3.0
-    , parsec ==3.1.14.0
-    , text ==1.2.4.0
-    , transformers ==0.5.6.2
-    , vector ==0.12.1.2
-    , xml-conduit ==1.9.0.0
-    , yaml ==0.11.5.0
+    , bytestring
+    , containers
+    , filepath
+    , http-client
+    , http-client-tls
+    , mustache
+    , network-uri
+    , parsec
+    , text
+    , transformers
+    , vector
+    , xml-conduit
+    , yaml
   default-language: Haskell2010
 
 executable onix-exe
@@ -67,7 +67,7 @@ executable onix-exe
   build-depends:
       base >=4.7 && <5
     , onix
-    , optparse-applicative ==0.16.1.0
+    , optparse-applicative
   default-language: Haskell2010
 
 test-suite onix-test
@@ -84,11 +84,11 @@ test-suite onix-test
       test
   ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
-      HUnit ==1.6.1.0
+      HUnit
     , base >=4.7 && <5
-    , containers ==0.6.2.1
+    , containers
     , onix
-    , text ==1.2.4.0
-    , vector ==0.12.1.2
-    , xml-conduit ==1.9.0.0
+    , text
+    , vector
+    , xml-conduit
   default-language: Haskell2010
diff --git a/package.yaml b/package.yaml
index 50e6ae6..070f802 100644
--- a/package.yaml
+++ b/package.yaml
@@ -29,19 +29,19 @@ library:
     - -fwarn-incomplete-patterns
     - -fwarn-incomplete-uni-patterns
   dependencies:
-    - mustache == 2.3.1
-    - text == 1.2.4.0
-    - yaml == 0.11.5.0
-    - vector == 0.12.1.2
-    - xml-conduit == 1.9.0.0
-    - parsec == 3.1.14.0
-    - containers == 0.6.2.1
-    - transformers == 0.5.6.2
-    - bytestring == 0.10.10.1
-    - filepath == 1.4.2.1
-    - http-client-tls == 0.3.5.3
-    - http-client == 0.6.4.1
-    - network-uri == 2.6.3.0
+    - mustache
+    - text
+    - yaml
+    - vector
+    - xml-conduit
+    - parsec
+    - containers
+    - transformers
+    - bytestring
+    - filepath
+    - http-client-tls
+    - http-client
+    - network-uri
 
 executables:
   onix-exe:
@@ -56,7 +56,7 @@ executables:
         -fwarn-incomplete-uni-patterns
     dependencies:
       - onix
-      - optparse-applicative == 0.16.1.0
+      - optparse-applicative
 
 tests:
   onix-test:
@@ -68,8 +68,8 @@ tests:
       - -with-rtsopts=-N
     dependencies:
       - onix
-      - HUnit == 1.6.1.0
-      - vector == 0.12.1.2
-      - xml-conduit == 1.9.0.0
-      - text == 1.2.4.0
-      - containers == 0.6.2.1
+      - HUnit
+      - vector
+      - xml-conduit
+      - text
+      - containers
diff --git a/stack.yaml b/stack.yaml
index daf1b09..0222475 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -18,7 +18,7 @@
 # resolver: ./custom-snapshot.yaml
 # resolver: https://example.com/snapshots/2018-01-01.yaml
 resolver:
-  url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/27.yaml
+  url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/23/25.yaml
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.
@@ -29,7 +29,6 @@ resolver:
 #   subdirs:
 #   - auto-update
 #   - wai
-allow-newer: true
 packages:
   - .
 # Dependency packages to be pulled from upstream that are not in the resolver.
@@ -41,10 +40,6 @@ build:
   library-profiling: true
   executable-profiling: true
 
-extra-deps:
-  - HUnit-1.6.1.0
-  - git: https://github.com/typeable/xsd-parser.git
-    commit: e08a37cf08674a492407b9b7f4a61e8faedb1590
 # - acme-missiles-0.3
 # - git: https://github.com/commercialhaskell/stack.git
 #   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
diff --git a/stack.yaml.lock b/stack.yaml.lock
index 952b0ee..760127d 100644
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -3,29 +3,11 @@
 # For more information, please see the documentation at:
 #   https://docs.haskellstack.org/en/stable/lock_files
 
-packages:
-- completed:
-    hackage: HUnit-1.6.1.0@sha256:62af6d70183d93944b98a8d9cb2ba4484b91303f74ebbb94425f7389d418c344,1572
-    pantry-tree:
-      size: 878
-      sha256: c42729ab00656f53d6a1114cf498574c62a8c595fa3d877639b5179a70dc6c8d
-  original:
-    hackage: HUnit-1.6.1.0
-- completed:
-    name: xsd-parser
-    version: 0.1.0.0
-    git: https://github.com/typeable/xsd-parser.git
-    pantry-tree:
-      size: 4810413
-      sha256: 4667e0d16862c182eb86d1d78a9cc390cd6d3f0012fa48957db477efa80f3281
-    commit: e08a37cf08674a492407b9b7f4a61e8faedb1590
-  original:
-    git: https://github.com/typeable/xsd-parser.git
-    commit: e08a37cf08674a492407b9b7f4a61e8faedb1590
+packages: []
 snapshots:
 - completed:
-    size: 533252
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/27.yaml
-    sha256: c2aaae52beeacf6a5727c1010f50e89d03869abfab6d2c2658ade9da8ed50c73
+    size: 684278
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/23/25.yaml
+    sha256: a3501d1b61a539371d85305fe73e1134fc08e7c97498a42952455f011fd97ecf
   original:
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/27.yaml
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/23/25.yaml