diff --git a/debian/changelog b/debian/changelog
index a10ad6e..dca3f82 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+python-castellan (3.7.1-2) UNRELEASED; urgency=medium
+
+  * Bump debhelper from old 11 to 12.
+    + Replace python_distutils buildsystem with pybuild.
+
+ -- Debian Janitor <janitor@jelmer.uk>  Wed, 16 Jun 2021 05:25:03 -0000
+
 python-castellan (3.7.1-1) experimental; urgency=medium
 
   * New upstream release.
diff --git a/debian/control b/debian/control
index e0ce67a..8992383 100644
--- a/debian/control
+++ b/debian/control
@@ -5,7 +5,7 @@
 Uploaders:
  Thomas Goirand <zigo@debian.org>,
 Build-Depends:
- debhelper-compat (= 11),
+ debhelper-compat (= 12),
  dh-python,
  openstack-pkg-tools,
  python3-all,
diff --git a/debian/rules b/debian/rules
index 43e4bae..e34dfd6 100755
--- a/debian/rules
+++ b/debian/rules
@@ -4,7 +4,7 @@
 include /usr/share/openstack-pkg-tools/pkgos.make
 
 %:
-	dh $@ --buildsystem=python_distutils --with python3,sphinxdoc
+	dh $@ --buildsystem=pybuild --with python3,sphinxdoc
 
 override_dh_auto_clean:
 	rm -rf build
@@ -32,5 +32,5 @@
 override_dh_sphinxdoc:
 ifeq (,$(findstring nodoc, $(DEB_BUILD_OPTIONS)))
 	PYTHONPATH=. python3 -m sphinx -b html doc/source debian/python-castellan-doc/usr/share/doc/python-castellan-doc/html
-	dh_sphinxdoc -O--buildsystem=python_distutils
+	dh_sphinxdoc -O--buildsystem=pybuild
 endif