diff --git a/docs/THIRDPARTY b/docs/THIRDPARTY
index 248dbc3908..156d864c65 100644
--- a/docs/THIRDPARTY
+++ b/docs/THIRDPARTY
@@ -1,4 +1,4 @@
-Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
 Upstream-Name: Zulip
 Upstream-Contact: Tim Abbott <tabbott@zulipchat.com>
 Source: https://zulipchat.com/