diff --git a/.circleci/config.yml b/.circleci/config.yml
index e57008bcd3..c87ece0bc2 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,7 +1,5 @@
 defaults: &defaults
   working_directory: ~/build
-  docker:
-    - image: alanz/haskell-hie-ci
   resource_class: large
   steps:
     - checkout
@@ -34,25 +32,10 @@ defaults: &defaults
           echo "export SKIP_CI=$SKIP_CI" >> $BASH_ENV
 
     - run:
-        name: Stack upgrade
+        name: Build
         command: |
           if [[ -z "$SKIP_CI" ]]; then
-            stack upgrade
-          fi
-
-    - run:
-        name: Stack setup
-        command: |
-          if [[ -z "$SKIP_CI" ]]; then
-            stack -j4 --stack-yaml=${STACK_FILE} setup
-          fi
-
-    - run:
-        name: Build (we need the exe for tests)
-        # need j1, else ghc-lib-parser triggers OOM
-        command: |
-          if [[ -z "$SKIP_CI" ]]; then
-            stack -j4 --stack-yaml=${STACK_FILE} install --no-terminal
+            stack -j4 --stack-yaml=${STACK_FILE} install --system-ghc --no-terminal
           fi
         no_output_timeout: 30m
 
@@ -60,7 +43,7 @@ defaults: &defaults
         name: Build Testsuite without running it
         command: |
           if [[ -z "$SKIP_CI" ]]; then
-            stack -j4 --stack-yaml=${STACK_FILE} build --test --no-run-tests --no-terminal
+            stack -j4 --stack-yaml=${STACK_FILE} build --system-ghc --test --no-run-tests --no-terminal
           fi
         no_output_timeout: 30m
 
@@ -70,22 +53,25 @@ defaults: &defaults
 
     - save_cache:
         key: v4-stack-cache-{{ arch }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "resolver.txt" }}
-        paths: &cache_paths
+        paths:
           - ~/.stack
 
 version: 2
 jobs:
   stackage-lts21:
+    docker:
+      - image: haskell:9.4.8-slim-buster
     environment:
       - STACK_FILE: "stack-lts21.yaml"
     <<: *defaults
 
   stackage-nightly:
+    docker:
+      - image: haskell:9.6.4-slim-buster
     environment:
       - STACK_FILE: "stack.yaml"
     <<: *defaults
 
-
 workflows:
   version: 2
   multiple-ghcs:
diff --git a/stack-lts21.yaml b/stack-lts21.yaml
index 92ff5a1a03..0471c79369 100644
--- a/stack-lts21.yaml
+++ b/stack-lts21.yaml
@@ -1,4 +1,4 @@
-resolver: lts-21.25 # ghc-9.4
+resolver: lts-21.25 # ghc-9.4.8
 
 packages:
   - .
diff --git a/stack.yaml b/stack.yaml
index 3f278f8a6d..2ede7e42b1 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,4 +1,4 @@
-resolver: nightly-2023-07-10 # ghc-9.6.2
+resolver: lts-22.9 # ghc-9.6.4
 
 packages:
   - .
@@ -20,25 +20,15 @@ extra-deps:
 - retrie-1.2.2
 - hiedb-0.5.0.1
 - implicit-hie-0.1.4.0
-- hie-bios-0.13.1
 - lsp-2.4.0.0
 - lsp-test-0.17.0.0
 - lsp-types-2.1.1.0
-- attoparsec-aeson-2.1.0.0
-- hw-fingertree-0.1.2.1
-- integer-conversion-0.1.0.1
 - monad-dijkstra-0.1.1.4
-- hw-prim-0.6.3.2
-- optparse-applicative-0.17.1.0
 
 # stan and friends
 - stan-0.1.2.0
-- clay-0.14.0
-- colourista-0.1.0.2
 - dir-traverse-0.2.3.0
 - extensions-0.1.0.1
-- relude-1.2.1.0
-- slist-0.2.1.0
 - tomland-1.3.3.2
 - trial-0.0.0.0
 - trial-optparse-applicative-0.0.0.0