1 files changed, 1 insertions, 1 deletions
diff --git a/develop/development/contributing_guide.html b/develop/development/contributing_guide.html
index 8a4fb5b6e9..dad5979ce7 100644
--- a/develop/development/contributing_guide.html
+++ b/develop/development/contributing_guide.html
@@ -405,7 +405,7 @@ in the format of <code>PRnumber.type</code>. The type can be one of the followin
 <p>This file will become part of our <a href="https://github.com/matrix-org/synapse/blob/master/CHANGES.md">changelog</a> at the next
 release, so the content of the file should be a short description of your
 change in the same style as the rest of the changelog. The file can contain Markdown
-formatting, and should end with a full stop (.) or an exclamation mark (!) for
+formatting, and must end with a full stop (.) or an exclamation mark (!) for
 consistency.</p>
 <p>Adding credits to the changelog is encouraged, we value your
 contributions and would like to have you shouted out in the release notes!</p>