diff --git a/.github/workflows/docker-action.yml b/.github/workflows/docker-action.yml
index eaacac9..1290355 100644
--- a/.github/workflows/docker-action.yml
+++ b/.github/workflows/docker-action.yml
@@ -3,7 +3,7 @@ name: Docker CI
 on:
   push:
     branches:
-      - master
+      - v8.18
   pull_request:
     branches:
       - '**'
@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         image:
-          - 'coqorg/coq:dev'
+          - 'coqorg/coq:8.18'
       fail-fast: false
     steps:
       - uses: actions/checkout@v3
diff --git a/.github/workflows/nix-action.yml b/.github/workflows/nix-action.yml
deleted file mode 100644
index 25264ba..0000000
--- a/.github/workflows/nix-action.yml
+++ /dev/null
@@ -1,47 +0,0 @@
-# This file was generated from `meta.yml`, please do not edit manually.
-# Follow the instructions on https://github.com/coq-community/templates to regenerate.
-name: Nix CI
-
-on:
-  push:
-    branches:
-      - master
-  pull_request:
-    paths:
-    - .github/workflows/**
-  pull_request_target:
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        overrides:
-          - 'coq = "master"'
-      fail-fast: false
-    steps:
-      - name: Determine which commit to test
-        run: |
-          if [[ ${{ github.event_name }} =~ "pull_request" ]]; then
-            merge_commit=$(git ls-remote ${{ github.event.repository.html_url }} refs/pull/${{ github.event.number }}/merge | cut -f1)
-            if [ -z "$merge_commit" ]; then
-              echo "tested_commit=${{ github.event.pull_request.head.sha }}" >> $GITHUB_ENV
-            else
-              echo "tested_commit=$merge_commit" >> $GITHUB_ENV
-            fi
-          else
-            echo "tested_commit=${{ github.sha }}" >> $GITHUB_ENV
-          fi
-      - uses: cachix/install-nix-action@v20
-        with:
-          nix_path: nixpkgs=channel:nixpkgs-unstable
-      - uses: cachix/cachix-action@v12
-        with:
-          name: coq-community
-          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
-          extraPullNames: coq, math-comp
-      - uses: actions/checkout@v3
-        with:
-          ref: ${{ env.tested_commit }}
-      - run: >
-          nix-build https://coq.inria.fr/nix/toolbox --argstr job stalmarck --arg override '{ ${{ matrix.overrides }}; stalmarck = builtins.filterSource (path: _: baseNameOf path != ".git") ./.; }'
diff --git a/README.md b/README.md
index 2e5b370..26ba8f4 100644
--- a/README.md
+++ b/README.md
@@ -5,18 +5,14 @@ Follow the instructions on https://github.com/coq-community/templates to regener
 # Stalmarck
 
 [![Docker CI][docker-action-shield]][docker-action-link]
-[![Nix CI][nix-action-shield]][nix-action-link]
 [![Contributing][contributing-shield]][contributing-link]
 [![Code of Conduct][conduct-shield]][conduct-link]
 [![Zulip][zulip-shield]][zulip-link]
 [![DOI][doi-shield]][doi-link]
 
-[docker-action-shield]: https://github.com/coq-community/stalmarck/workflows/Docker%20CI/badge.svg?branch=master
+[docker-action-shield]: https://github.com/coq-community/stalmarck/workflows/Docker%20CI/badge.svg?branch=v8.18
 [docker-action-link]: https://github.com/coq-community/stalmarck/actions?query=workflow:"Docker%20CI"
 
-[nix-action-shield]: https://github.com/coq-community/stalmarck/workflows/Nix%20CI/badge.svg?branch=master
-[nix-action-link]: https://github.com/coq-community/stalmarck/actions?query=workflow:"Nix%20CI"
-
 [contributing-shield]: https://img.shields.io/badge/contributions-welcome-%23f7931e.svg
 [contributing-link]: https://github.com/coq-community/manifesto/blob/master/CONTRIBUTING.md
 
@@ -41,7 +37,7 @@ algorithm in Coq.
 - Coq-community maintainer(s):
   - Karl Palmskog ([**@palmskog**](https://github.com/palmskog))
 - License: [GNU Lesser General Public License v2.1 or later](LICENSE)
-- Compatible Coq versions: Coq master (use the corresponding branch or release for other Coq versions)
+- Compatible Coq versions: 8.18 (use the corresponding branch or release for other Coq versions)
 - Additional dependencies: none
 - Coq namespace: `Stalmarck.Algorithm`
 - Related publication(s):
diff --git a/coq-stalmarck-tactic.opam b/coq-stalmarck-tactic.opam
index bd80662..8cc6646 100644
--- a/coq-stalmarck-tactic.opam
+++ b/coq-stalmarck-tactic.opam
@@ -13,7 +13,7 @@ build: ["dune" "build" "-p" name "-j" jobs]
 depends: [
   "ocaml" {>= "4.09.0"}
   "dune" {>= "2.8"}
-  "coq" {= "dev"}
+  "coq" {>= "8.18" & < "8.19"}
   "coq-stalmarck" {= version}
 ]
 
diff --git a/coq-stalmarck.opam b/coq-stalmarck.opam
index ef29c4a..b78e2c6 100644
--- a/coq-stalmarck.opam
+++ b/coq-stalmarck.opam
@@ -18,7 +18,7 @@ algorithm in Coq."""
 build: [make "-j%{jobs}%"]
 install: [make "install"]
 depends: [
-  "coq" {= "dev"}
+  "coq" {>= "8.18" & < "8.19"}
 ]
 
 tags: [
diff --git a/meta.yml b/meta.yml
index b8dfd26..3f1f38c 100644
--- a/meta.yml
+++ b/meta.yml
@@ -4,10 +4,9 @@ shortname: stalmarck
 organization: coq-community
 community: true
 action: true
-nix: true
 doi: 10.1007/3-540-44659-1_24
 plugin: true
-branch: master
+branch: 'v8.18'
 dune: false
 
 synopsis: Verified implementation of Stålmarck's algorithm for proving tautologies in Coq
@@ -40,11 +39,11 @@ license:
   identifier: LGPL-2.1-or-later
 
 supported_coq_versions:
-  text: Coq master (use the corresponding branch or release for other Coq versions)
-  opam: '{= "dev"}'
+  text: 8.18 (use the corresponding branch or release for other Coq versions)
+  opam: '{>= "8.18" & < "8.19"}'
 
 tested_coq_nix_versions:
-- coq_version: 'master'
+- coq_version: '8.18'
 
 tested_coq_opam_versions:
 - version: 'dev'