diff --git a/src/pycalver/patterns.py b/src/pycalver/patterns.py
index 863eb16..a54a803 100644
--- a/src/pycalver/patterns.py
+++ b/src/pycalver/patterns.py
@@ -62,6 +62,7 @@ PATTERN_ESCAPES = [
     ("."     , "\u005c."),
     ("+"     , "\u005c+"),
     ("*"     , "\u005c*"),
+    ("?"     , "\u005c?"),
     ("{"     , "\u005c{"),
     ("}"     , "\u005c}"),
     ("["     , "\u005c["),