diff --git a/.github/workflows/test-backends.yml b/.github/workflows/test-backends.yml
index fae6ef776..7a7dc0d31 100644
--- a/.github/workflows/test-backends.yml
+++ b/.github/workflows/test-backends.yml
@@ -20,75 +20,15 @@ env:
 
 jobs:
 
-  lammps-develop:
+  lammps-stable_29Aug2024:
     name: LAMMPS (develop)
     uses: ./.github/workflows/backend-template.yml
     with:
       backend_name: LAMMPS
       backend_repo: lammps/lammps
-      backend_repo_ref: develop
+      backend_repo_ref: stable_29Aug2024
       container_name: CentOS9-devel
       path_compile_script: devel-tools/compile-lammps.sh
       test_lib_directory: lammps/tests/library
       test_interface_directory: lammps/tests/interface
       rpath_exe: install/bin/lmp
-
-  namd-main:
-    name: NAMD (main)
-    uses: ./.github/workflows/backend-template.yml
-    with:
-      backend_name: NAMD
-      backend_repo: Colvars/namd
-      backend_repo_ref: main
-      path_compile_script: devel-tools/compile-namd.sh
-      test_lib_directory: namd/tests/library
-      test_interface_directory: namd/tests/interface
-      rpath_exe: Linux-x86_64-g++.mpi/namd3
-      container_name: CentOS7-devel
-    secrets:
-      # Choice of license by UIUC prevents sharing the code, hence the secret
-      private_key: ${{ secrets.PULL_NAMD_KEY }}
-
-  vmd-cvs:
-    name: VMD
-    uses: ./.github/workflows/backend-template.yml
-    with:
-      backend_name: VMD
-      backend_repo: Colvars/vmd
-      backend_repo_ref: master
-      container_name: CentOS7-devel
-      # Special variable for VMD test case since it's the only one
-      # which needs to checkout 2 repos
-      vmd_plugins_repo: Colvars/vmd-plugins
-      path_compile_script: devel-tools/compile-vmd.sh
-      test_interface_directory: vmd/tests/interface
-      rpath_exe: install/vmd
-    secrets:
-      # Per-repository secret
-      private_key: ${{ secrets.PULL_VMD_KEY }}
-      private_key_vmd_plugins: ${{ secrets.PULL_VMD_PLUGINS_KEY }}
-
-  gromacs-2023:
-    name: GROMACS (release-2023)
-    uses: ./.github/workflows/backend-template.yml
-    with:
-      backend_name: GROMACS-2023
-      backend_repo: gromacs/gromacs
-      backend_repo_ref: release-2023
-      container_name: CentOS9-devel
-      path_compile_script: devel-tools/compile-gromacs.sh
-      test_lib_directory: gromacs/tests/library
-      rpath_exe: install/bin/gmx_mpi_d
-
-  gromacs-main:
-    name: GROMACS (main)
-    uses: ./.github/workflows/backend-template.yml
-    with:
-      backend_name: GROMACS-main
-      backend_repo: gromacs/gromacs
-      backend_repo_ref: main
-      container_name: CentOS9-devel
-      path_compile_script: devel-tools/compile-gromacs.sh
-      test_lib_directory: gromacs/tests/library
-      test_interface_directory: gromacs/tests/interface
-      rpath_exe: install/bin/gmx_mpi_d