diff --git a/base.json b/base.json
index 0b0ddd9..fe95302 100644
--- a/base.json
+++ b/base.json
@@ -18,7 +18,7 @@
     {
       "fileMatch": ["^Makefile$"],
       "matchStrings": [
-        "# renovate: datasource=(?<datasource>\\S+) depName=(?<depName>\\S+)( versioning=(?<versioning>.*?))?\\n.*?_VERSION (:|?)= (?<currentValue>.*)\\s"
+        "# renovate: datasource=(?<datasource>\\S+) depName=(?<depName>\\S+)( versioning=(?<versioning>.*?))?\\n.*?_VERSION (:|\\?)= (?<currentValue>.*)\\s"
       ]
     }
   ],