diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
index 136d1f6..8c873de 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: 0.19.20240708
+# version: 0.19.20250216
 #
-# REGENDATA ("0.19.20240708",["github","ekg-core.cabal"])
+# REGENDATA ("0.19.20250216",["github","ekg-core.cabal"])
 #
 name: Haskell-CI
 on:
@@ -19,7 +19,7 @@ on:
 jobs:
   linux:
     name: Haskell-CI - Linux - ${{ matrix.compiler }}
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     timeout-minutes:
       60
     container:
@@ -28,14 +28,19 @@ jobs:
     strategy:
       matrix:
         include:
+          - compiler: ghc-9.12.1
+            compilerKind: ghc
+            compilerVersion: 9.12.1
+            setup-method: ghcup
+            allow-failure: false
           - compiler: ghc-9.10.1
             compilerKind: ghc
             compilerVersion: 9.10.1
             setup-method: ghcup
             allow-failure: false
-          - compiler: ghc-9.8.2
+          - compiler: ghc-9.8.4
             compilerKind: ghc
-            compilerVersion: 9.8.2
+            compilerVersion: 9.8.4
             setup-method: ghcup
             allow-failure: false
           - compiler: ghc-9.6.6
@@ -95,15 +100,29 @@ jobs:
             allow-failure: false
       fail-fast: false
     steps:
-      - name: apt
+      - name: apt-get install
         run: |
           apt-get update
           apt-get install -y --no-install-recommends gnupg ca-certificates dirmngr curl git software-properties-common libtinfo5 libnuma-dev
+      - name: Install GHCup
+        run: |
           mkdir -p "$HOME/.ghcup/bin"
           curl -sL https://downloads.haskell.org/ghcup/0.1.30.0/x86_64-linux-ghcup-0.1.30.0 > "$HOME/.ghcup/bin/ghcup"
           chmod a+x "$HOME/.ghcup/bin/ghcup"
-          "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
+      - name: Install cabal-install
+        run: |
           "$HOME/.ghcup/bin/ghcup" install cabal 3.12.1.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
+          echo "CABAL=$HOME/.ghcup/bin/cabal-3.12.1.0 -vnormal+nowrap" >> "$GITHUB_ENV"
+      - name: Install GHC (GHCup)
+        if: matrix.setup-method == 'ghcup'
+        run: |
+          "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
+          HC=$("$HOME/.ghcup/bin/ghcup" whereis ghc "$HCVER")
+          HCPKG=$(echo "$HC" | sed 's#ghc$#ghc-pkg#')
+          HADDOCK=$(echo "$HC" | sed 's#ghc$#haddock#')
+          echo "HC=$HC" >> "$GITHUB_ENV"
+          echo "HCPKG=$HCPKG" >> "$GITHUB_ENV"
+          echo "HADDOCK=$HADDOCK" >> "$GITHUB_ENV"
         env:
           HCKIND: ${{ matrix.compilerKind }}
           HCNAME: ${{ matrix.compiler }}
@@ -114,21 +133,12 @@ jobs:
           echo "LANG=C.UTF-8" >> "$GITHUB_ENV"
           echo "CABAL_DIR=$HOME/.cabal" >> "$GITHUB_ENV"
           echo "CABAL_CONFIG=$HOME/.cabal/config" >> "$GITHUB_ENV"
-          HCDIR=/opt/$HCKIND/$HCVER
-          HC=$("$HOME/.ghcup/bin/ghcup" whereis ghc "$HCVER")
-          HCPKG=$(echo "$HC" | sed 's#ghc$#ghc-pkg#')
-          HADDOCK=$(echo "$HC" | sed 's#ghc$#haddock#')
-          echo "HC=$HC" >> "$GITHUB_ENV"
-          echo "HCPKG=$HCPKG" >> "$GITHUB_ENV"
-          echo "HADDOCK=$HADDOCK" >> "$GITHUB_ENV"
-          echo "CABAL=$HOME/.ghcup/bin/cabal-3.12.1.0 -vnormal+nowrap" >> "$GITHUB_ENV"
           HCNUMVER=$(${HC} --numeric-version|perl -ne '/^(\d+)\.(\d+)\.(\d+)(\.(\d+))?$/; print(10000 * $1 + 100 * $2 + ($3 == 0 ? $5 != 1 : $3))')
           echo "HCNUMVER=$HCNUMVER" >> "$GITHUB_ENV"
           echo "ARG_TESTS=--enable-tests" >> "$GITHUB_ENV"
           echo "ARG_BENCH=--enable-benchmarks" >> "$GITHUB_ENV"
           echo "HEADHACKAGE=false" >> "$GITHUB_ENV"
           echo "ARG_COMPILER=--$HCKIND --with-compiler=$HC" >> "$GITHUB_ENV"
-          echo "GHCJSARITH=0" >> "$GITHUB_ENV"
         env:
           HCKIND: ${{ matrix.compilerKind }}
           HCNAME: ${{ matrix.compiler }}
@@ -241,8 +251,8 @@ jobs:
           rm -f cabal.project.local
           $CABAL v2-build $ARG_COMPILER --disable-tests --disable-benchmarks all
       - name: save cache
-        uses: actions/cache/save@v4
         if: always()
+        uses: actions/cache/save@v4
         with:
           key: ${{ runner.os }}-${{ matrix.compiler }}-${{ github.sha }}
           path: ~/.cabal/store
diff --git a/ekg-core.cabal b/ekg-core.cabal
index 2d581d4..3141c8e 100644
--- a/ekg-core.cabal
+++ b/ekg-core.cabal
@@ -27,8 +27,9 @@ tested-with:
    || ==9.4.8
    || ==9.6.4
    || ==9.6.6
-   || ==9.8.2
+   || ==9.8.4
    || ==9.10.1
+   || ==9.12.1
 
 library
   exposed-modules:
@@ -45,8 +46,8 @@ library
     System.Metrics.ThreadId
 
   build-depends:
-      base                  >=4.6 && <4.21
-    , containers            >=0.5 && <0.8
+      base                  >=4.6 && <4.22
+    , containers            >=0.5 && <0.9
     , text                  <2.2
     , unordered-containers  <0.3