diff --git a/env/sles15/x86_64/admin/unstable/spack.yaml b/env/sles15/x86_64/admin/unstable/spack.yaml
index 057077f..3ed3982 100644
--- a/env/sles15/x86_64/admin/unstable/spack.yaml
+++ b/env/sles15/x86_64/admin/unstable/spack.yaml
@@ -9,6 +9,7 @@ spack:
         - cp2k@2024.1/2jesise #~cuda
         - cp2k@2024.1/zqm5fme #+cuda
         - quantum-espresso@7.3.1/n6mulig #~cuda
+        - opal@2024.1.0/mhg3mdx
     - gcc_12.3_openmpi:
         - gromacs@2024.1/3n7qspb #+cuda
   include: