diff --git a/debian/changelog b/debian/changelog
index 1e56be4..acfef2b 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -2,6 +2,7 @@
 
   * Trim trailing whitespace.
   * Remove empty leading paragraph in Description.
+  * Upgrade to newer source format 3.0 (quilt).
 
  -- Debian Janitor <janitor@jelmer.uk>  Wed, 22 Sep 2021 23:29:33 -0000
 
diff --git a/debian/source/format b/debian/source/format
new file mode 100644
index 0000000..163aaf8
--- /dev/null
+++ b/debian/source/format
@@ -0,0 +1 @@
+3.0 (quilt)