diff --git a/.github/workflows/nix-action-8.20.yml b/.github/workflows/nix-action-8.20.yml
index 64fd0ec..3528891 100644
--- a/.github/workflows/nix-action-8.20.yml
+++ b/.github/workflows/nix-action-8.20.yml
@@ -2150,6 +2150,63 @@ jobs:
       name: Building/fetching current CI target
       run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "8.20" --argstr
         job "interval"
+  iris:
+    needs:
+    - coq
+    - stdpp
+    runs-on: ubuntu-latest
+    steps:
+    - name: Determine which commit to initially checkout
+      run: "if [ ${{ github.event_name }} = \"push\" ]; then\n  echo \"target_commit=${{
+        github.sha }}\" >> $GITHUB_ENV\nelse\n  echo \"target_commit=${{ github.event.pull_request.head.sha
+        }}\" >> $GITHUB_ENV\nfi\n"
+    - name: Git checkout
+      uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+        ref: ${{ env.target_commit }}
+    - name: Determine which commit to test
+      run: "if [ ${{ github.event_name }} = \"push\" ]; then\n  echo \"tested_commit=${{
+        github.sha }}\" >> $GITHUB_ENV\nelse\n  merge_commit=$(git ls-remote ${{ github.event.repository.html_url
+        }} refs/pull/${{ github.event.number }}/merge | cut -f1)\n  mergeable=$(git
+        merge --no-commit --no-ff ${{ github.event.pull_request.base.sha }} > /dev/null
+        2>&1; echo $?; git merge --abort > /dev/null 2>&1 || true)\n  if [ -z \"$merge_commit\"\
+        \ -o \"x$mergeable\" != \"x0\" ]; then\n    echo \"tested_commit=${{ github.event.pull_request.head.sha
+        }}\" >> $GITHUB_ENV\n  else\n    echo \"tested_commit=$merge_commit\" >> $GITHUB_ENV\n\
+        \  fi\nfi\n"
+    - name: Git checkout
+      uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+        ref: ${{ env.tested_commit }}
+    - name: Cachix install
+      uses: cachix/install-nix-action@v27
+      with:
+        nix_path: nixpkgs=channel:nixpkgs-unstable
+    - name: Cachix setup coq-community
+      uses: cachix/cachix-action@v15
+      with:
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, math-comp
+        name: coq-community
+    - id: stepCheck
+      name: Checking presence of CI target iris
+      run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr
+        bundle \"8.20\" --argstr job \"iris\" \\\n   --dry-run 2>&1 > /dev/null)\n
+        echo $nb_dry_run\necho status=$(echo $nb_dry_run | grep \"built:\" | sed \"\
+        s/.*/built/\") >> $GITHUB_OUTPUT\n"
+    - if: steps.stepCheck.outputs.status == 'built'
+      name: 'Building/fetching previous CI target: coq'
+      run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "8.20" --argstr
+        job "coq"
+    - if: steps.stepCheck.outputs.status == 'built'
+      name: 'Building/fetching previous CI target: stdpp'
+      run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "8.20" --argstr
+        job "stdpp"
+    - if: steps.stepCheck.outputs.status == 'built'
+      name: Building/fetching current CI target
+      run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "8.20" --argstr
+        job "iris"
   itauto:
     needs:
     - coq
@@ -5117,6 +5174,58 @@ jobs:
       name: Building/fetching current CI target
       run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "8.20" --argstr
         job "stalmarck-tactic"
+  stdpp:
+    needs:
+    - coq
+    runs-on: ubuntu-latest
+    steps:
+    - name: Determine which commit to initially checkout
+      run: "if [ ${{ github.event_name }} = \"push\" ]; then\n  echo \"target_commit=${{
+        github.sha }}\" >> $GITHUB_ENV\nelse\n  echo \"target_commit=${{ github.event.pull_request.head.sha
+        }}\" >> $GITHUB_ENV\nfi\n"
+    - name: Git checkout
+      uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+        ref: ${{ env.target_commit }}
+    - name: Determine which commit to test
+      run: "if [ ${{ github.event_name }} = \"push\" ]; then\n  echo \"tested_commit=${{
+        github.sha }}\" >> $GITHUB_ENV\nelse\n  merge_commit=$(git ls-remote ${{ github.event.repository.html_url
+        }} refs/pull/${{ github.event.number }}/merge | cut -f1)\n  mergeable=$(git
+        merge --no-commit --no-ff ${{ github.event.pull_request.base.sha }} > /dev/null
+        2>&1; echo $?; git merge --abort > /dev/null 2>&1 || true)\n  if [ -z \"$merge_commit\"\
+        \ -o \"x$mergeable\" != \"x0\" ]; then\n    echo \"tested_commit=${{ github.event.pull_request.head.sha
+        }}\" >> $GITHUB_ENV\n  else\n    echo \"tested_commit=$merge_commit\" >> $GITHUB_ENV\n\
+        \  fi\nfi\n"
+    - name: Git checkout
+      uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+        ref: ${{ env.tested_commit }}
+    - name: Cachix install
+      uses: cachix/install-nix-action@v27
+      with:
+        nix_path: nixpkgs=channel:nixpkgs-unstable
+    - name: Cachix setup coq-community
+      uses: cachix/cachix-action@v15
+      with:
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, math-comp
+        name: coq-community
+    - id: stepCheck
+      name: Checking presence of CI target stdpp
+      run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr
+        bundle \"8.20\" --argstr job \"stdpp\" \\\n   --dry-run 2>&1 > /dev/null)\n
+        echo $nb_dry_run\necho status=$(echo $nb_dry_run | grep \"built:\" | sed \"\
+        s/.*/built/\") >> $GITHUB_OUTPUT\n"
+    - if: steps.stepCheck.outputs.status == 'built'
+      name: 'Building/fetching previous CI target: coq'
+      run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "8.20" --argstr
+        job "coq"
+    - if: steps.stepCheck.outputs.status == 'built'
+      name: Building/fetching current CI target
+      run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "8.20" --argstr
+        job "stdpp"
   vscoq-language-server:
     needs:
     - coq
diff --git a/.nix/nixpkgs.nix b/.nix/nixpkgs.nix
index 535644a..0e85c11 100644
--- a/.nix/nixpkgs.nix
+++ b/.nix/nixpkgs.nix
@@ -1,4 +1,4 @@
 fetchTarball {
-    url = https://github.com/NixOS/nixpkgs/archive/88f31ac8837ab15748102da8bbc6e96a9330be0d.tar.gz;
-    sha256 = "05bbc8cak5fbb2xic3zr6j54sivg5pra8567zs33ync85scrfgah";
-  }
+         url = https://github.com/vbgl/nixpkgs/archive/f9c95e2357b0e7d1be8b91becd61d17e08e814a1.tar.gz;
+         sha256 = "0m6qn2cnk333gq651dn5qj2i2caf7zch7ns11b21z62a04y6j3aj";
+       }