diff --git a/python/damask/solver/_marc.py b/python/damask/solver/_marc.py
index 1de16915d..3b03443bb 100644
--- a/python/damask/solver/_marc.py
+++ b/python/damask/solver/_marc.py
@@ -3,7 +3,7 @@ import shlex
 import re
 from pathlib import Path
 
-_marc_version = 2021.2
+_marc_version = '2021.2'
 _marc_root = '/opt/msc'
 _damask_root = str(Path(__file__).parents[3])