diff --git a/.github/workflows/test_eessi.yml b/.github/workflows/test_eessi.yml
index 48c41c7ce0..da1379043a 100644
--- a/.github/workflows/test_eessi.yml
+++ b/.github/workflows/test_eessi.yml
@@ -28,6 +28,7 @@ jobs:
         - eessi-2023.06-eb-4.7.2-system.yml
         - eessi-2023.06-eb-4.8.0-2021a.yml
         - eessi-2023.06-eb-4.8.0-system.yml
+        - eessi-2023.06-eb-4.8.0-2021b.yml
     steps:
         - name: Check out software-layer repository
           uses: actions/checkout@93ea575cb5d8a053eaa0ac8fa3b40d7e05a33cc8 # v3.1.0
diff --git a/eessi-2023.06-eb-4.8.0-2021b.yml b/eessi-2023.06-eb-4.8.0-2021b.yml
new file mode 100644
index 0000000000..477ba6320c
--- /dev/null
+++ b/eessi-2023.06-eb-4.8.0-2021b.yml
@@ -0,0 +1,7 @@
+easyconfigs:
+  - MPFR-4.1.0-GCCcore-11.2.0.eb:
+      # use patch for MPFR 4.1.0 to fix failing tsprintf test with glibc >= 2.37,
+      # see https://github.com/easybuilders/easybuild-easyconfigs/pull/18746
+      options:
+        from-pr: 18746
+  - OpenFOAM-v2112-foss-2021b.eb