diff --git a/config/aerc.conf b/config/aerc.conf
index 41d4b1f..8b3ac3a 100644
--- a/config/aerc.conf
+++ b/config/aerc.conf
@@ -68,7 +68,7 @@ alternatives=text/plain,text/html
 # You can also match on non-mimetypes, by prefixing with the header to match
 # against (non-case-sensitive) and a comma, e.g. subject,text will match a
 # subject which contains "text". Use header,~regex to match against a regex.
-subject,~PATCH=contrib/hldiff.py
+subject,~^\[PATCH=contrib/hldiff.py
 text/html=contrib/html
 text/*=contrib/plaintext.py