diff --git a/.github/workflows/ci-ubuntu.yml b/.github/workflows/ci-ubuntu.yml
index 2ecc969589..51c5f7b09c 100644
--- a/.github/workflows/ci-ubuntu.yml
+++ b/.github/workflows/ci-ubuntu.yml
@@ -8,6 +8,7 @@ on:
     branches:
       - master
       - experimental
+  merge_group:
 
 ########################################################################
 ## CONFIGURATION
@@ -71,16 +72,15 @@ jobs:
 
       - name: Initialise variables
         run: |
-          if [[ '${{ github.ref }}' == 'refs/heads/master' \
-             || '${{ github.base_ref }}' == 'master' ]]; then
-            # Pick Agda version for master
-            echo "AGDA_COMMIT=tags/v2.6.4" >> $GITHUB_ENV;
-            echo "AGDA_HTML_DIR=html/master" >> $GITHUB_ENV
-          elif [[ '${{ github.ref }}' == 'refs/heads/experimental' \
-               || '${{ github.base_ref }}' == 'experimental' ]]; then
+          if [[ '${{ github.ref }}' == 'refs/heads/experimental' \
+             || '${{ github.base_ref }}' == 'experimental' ]]; then
             # Pick Agda version for experimental
             echo "AGDA_COMMIT=4d36cb37f8bfb765339b808b13356d760aa6f0ec" >> $GITHUB_ENV;
             echo "AGDA_HTML_DIR=html/experimental" >> $GITHUB_ENV
+          else
+            # Pick Agda version for master
+            echo "AGDA_COMMIT=tags/v2.6.4" >> $GITHUB_ENV;
+            echo "AGDA_HTML_DIR=html/master" >> $GITHUB_ENV
           fi
 
           if [[ '${{ github.ref }}' == 'refs/heads/master' \
diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
index b8c55c19be..5f9fa86b50 100644
--- a/.github/workflows/haskell-ci.yml
+++ b/.github/workflows/haskell-ci.yml
@@ -8,9 +8,9 @@
 #
 # For more information, see https://github.com/haskell-CI/haskell-ci
 #
-# version: 0.17.20230824
+# version: 0.17.20231010
 #
-# REGENDATA ("0.17.20230824",["github","--no-cabal-check","agda-stdlib-utils.cabal"])
+# REGENDATA ("0.17.20231010",["github","--no-cabal-check","agda-stdlib-utils.cabal"])
 #
 name: Haskell-CI
 on:
@@ -32,6 +32,7 @@ on:
       - agda-stdlib-utils.cabal
       - cabal.haskell-ci
       - "*.hs"
+  merge_group:
 jobs:
   linux:
     name: Haskell-CI - Linux - ${{ matrix.compiler }}
@@ -44,19 +45,19 @@ jobs:
     strategy:
       matrix:
         include:
-          - compiler: ghc-9.8.0.20230822
+          - compiler: ghc-9.8.1
             compilerKind: ghc
-            compilerVersion: 9.8.0.20230822
+            compilerVersion: 9.8.1
             setup-method: ghcup
-            allow-failure: true
-          - compiler: ghc-9.6.2
+            allow-failure: false
+          - compiler: ghc-9.6.3
             compilerKind: ghc
-            compilerVersion: 9.6.2
+            compilerVersion: 9.6.3
             setup-method: ghcup
             allow-failure: false
-          - compiler: ghc-9.4.6
+          - compiler: ghc-9.4.7
             compilerKind: ghc
-            compilerVersion: 9.4.6
+            compilerVersion: 9.4.7
             setup-method: ghcup
             allow-failure: false
           - compiler: ghc-9.2.8
@@ -94,7 +95,6 @@ jobs:
             mkdir -p "$HOME/.ghcup/bin"
             curl -sL https://downloads.haskell.org/ghcup/0.1.19.5/x86_64-linux-ghcup-0.1.19.5 > "$HOME/.ghcup/bin/ghcup"
             chmod a+x "$HOME/.ghcup/bin/ghcup"
-            "$HOME/.ghcup/bin/ghcup" config add-release-channel https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-prereleases-0.0.7.yaml;
             "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
             "$HOME/.ghcup/bin/ghcup" install cabal 3.10.1.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
           else
@@ -104,7 +104,6 @@ jobs:
             mkdir -p "$HOME/.ghcup/bin"
             curl -sL https://downloads.haskell.org/ghcup/0.1.19.5/x86_64-linux-ghcup-0.1.19.5 > "$HOME/.ghcup/bin/ghcup"
             chmod a+x "$HOME/.ghcup/bin/ghcup"
-            "$HOME/.ghcup/bin/ghcup" config add-release-channel https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-prereleases-0.0.7.yaml;
             "$HOME/.ghcup/bin/ghcup" install cabal 3.10.1.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
           fi
         env:
@@ -138,7 +137,7 @@ jobs:
           echo "HCNUMVER=$HCNUMVER" >> "$GITHUB_ENV"
           echo "ARG_TESTS=--enable-tests" >> "$GITHUB_ENV"
           echo "ARG_BENCH=--enable-benchmarks" >> "$GITHUB_ENV"
-          if [ $((HCNUMVER >= 90800)) -ne 0 ] ; then echo "HEADHACKAGE=true" >> "$GITHUB_ENV" ; else echo "HEADHACKAGE=false" >> "$GITHUB_ENV" ; fi
+          echo "HEADHACKAGE=false" >> "$GITHUB_ENV"
           echo "ARG_COMPILER=--$HCKIND --with-compiler=$HC" >> "$GITHUB_ENV"
           echo "GHCJSARITH=0" >> "$GITHUB_ENV"
         env:
@@ -167,18 +166,6 @@ jobs:
           repository hackage.haskell.org
             url: http://hackage.haskell.org/
           EOF
-          if $HEADHACKAGE; then
-          cat >> $CABAL_CONFIG <<EOF
-          repository head.hackage.ghc.haskell.org
-             url: https://ghc.gitlab.haskell.org/head.hackage/
-             secure: True
-             root-keys: 7541f32a4ccca4f97aea3b22f5e593ba2c0267546016b992dfadcd2fe944e55d
-                        26021a13b401500c8eb2761ca95c61f2d625bfef951b939a8124ed12ecf07329
-                        f76d08be13e9a61a377a85e2fb63f4c5435d40f8feb3e12eb05905edb8cdea89
-             key-threshold: 3
-          active-repositories: hackage.haskell.org, head.hackage.ghc.haskell.org:override
-          EOF
-          fi
           cat >> $CABAL_CONFIG <<EOF
           program-default-options
             ghc-options: $GHCJOBS +RTS -M3G -RTS
@@ -230,9 +217,6 @@ jobs:
           echo "    ghc-options: -Werror=missing-methods" >> cabal.project
           cat >> cabal.project <<EOF
           EOF
-          if $HEADHACKAGE; then
-          echo "allow-newer: $($HCPKG list --simple-output | sed -E 's/([a-zA-Z-]+)-[0-9.]+/*:\1,/g')" >> cabal.project
-          fi
           $HCPKG list --simple-output --names-only | perl -ne 'for (split /\s+/) { print "constraints: $_ installed\n" unless /^(agda-stdlib-utils)$/; }' >> cabal.project.local
           cat cabal.project
           cat cabal.project.local
diff --git a/agda-stdlib-utils.cabal b/agda-stdlib-utils.cabal
index a482bee069..3accc6972e 100644
--- a/agda-stdlib-utils.cabal
+++ b/agda-stdlib-utils.cabal
@@ -6,9 +6,9 @@ description:     Helper programs for setting up the Agda standard library.
 license:         MIT
 
 tested-with:
-  GHC == 9.8.0
-  GHC == 9.6.2
-  GHC == 9.4.6
+  GHC == 9.8.1
+  GHC == 9.6.3
+  GHC == 9.4.7
   GHC == 9.2.8
   GHC == 9.0.2
   GHC == 8.10.7