diff -pruN 1:2.1.29-1/debian/changelog 1:2.1.29-1ubuntu3/debian/changelog
--- 1:2.1.29-1/debian/changelog	2018-09-05 05:03:24.000000000 +0000
+++ 1:2.1.29-1ubuntu3/debian/changelog	2020-03-19 10:09:33.000000000 +0000
@@ -1,3 +1,17 @@
+mailman (1:2.1.29-1ubuntu3) focal; urgency=medium
+
+  * Build-depend on python-all-dev.
+  * Build using python2.
+  * Use python2 in the postinst and the autopkg test.
+
+ -- Matthias Klose <doko@ubuntu.com>  Thu, 19 Mar 2020 11:09:33 +0100
+
+mailman (1:2.1.29-1build1) focal; urgency=medium
+
+  * No-change rebuild to generate dependencies on python2.
+
+ -- Matthias Klose <doko@ubuntu.com>  Tue, 17 Dec 2019 12:36:24 +0000
+
 mailman (1:2.1.29-1) unstable; urgency=medium
 
   * New upstream release.
diff -pruN 1:2.1.29-1/debian/control 1:2.1.29-1ubuntu3/debian/control
--- 1:2.1.29-1/debian/control	2018-06-23 13:33:50.000000000 +0000
+++ 1:2.1.29-1ubuntu3/debian/control	2020-03-18 14:22:16.000000000 +0000
@@ -3,7 +3,7 @@ Section: mail
 Priority: optional
 Maintainer: Mailman for Debian <pkg-mailman-hackers@lists.alioth.debian.org>
 Uploaders: Thijs Kinkhorst <thijs@debian.org>,
-Build-Depends: debhelper (>= 11), autoconf, python-dev,
+Build-Depends: debhelper (>= 11), autoconf, python-all-dev,
  gettext, python-dnspython, dh-python
 Standards-Version: 4.1.4
 Homepage: http://www.list.org/
diff -pruN 1:2.1.29-1/debian/postinst 1:2.1.29-1ubuntu3/debian/postinst
--- 1:2.1.29-1/debian/postinst	2018-06-23 14:26:09.000000000 +0000
+++ 1:2.1.29-1ubuntu3/debian/postinst	2020-03-18 19:53:20.000000000 +0000
@@ -10,7 +10,7 @@
 
 PACKAGE=mailman
 DIRLIST="/usr/lib/mailman/Mailman /usr/lib/mailman/bin /usr/lib/mailman/cron /usr/lib/mailman/scripts"
-PYLIBDIR="/usr/lib/python`python -c 'import sys; print sys.version[:3]'`"
+PYLIBDIR="/usr/lib/python`python2 -c 'import sys; print sys.version[:3]'`"
 
 if [ "$1" = "configure" ]; then
 
diff -pruN 1:2.1.29-1/debian/rules 1:2.1.29-1ubuntu3/debian/rules
--- 1:2.1.29-1/debian/rules	2018-06-23 13:14:21.000000000 +0000
+++ 1:2.1.29-1ubuntu3/debian/rules	2020-03-18 14:24:29.000000000 +0000
@@ -35,6 +35,7 @@ debian/po/templates.pot: debian/template
 Makefile:
 	dh_autoreconf
 	./configure --prefix=/var/lib/$(package) --with-username=list \
+		--with-python=/usr/bin/python2 \
 		--with-groupname=list \
 		--with-mail-gid=daemon --with-cgi-gid=www-data \
 		--without-permcheck --with-mailhost=localhost \
diff -pruN 1:2.1.29-1/debian/tests/mailman 1:2.1.29-1ubuntu3/debian/tests/mailman
--- 1:2.1.29-1/debian/tests/mailman	2018-06-23 13:14:21.000000000 +0000
+++ 1:2.1.29-1ubuntu3/debian/tests/mailman	2020-03-19 10:09:11.000000000 +0000
@@ -3,4 +3,4 @@
 # Testing mailman
 #----------------
 set -e
-python `dirname $0`/test-mailman.py 2>&1
+python2 `dirname $0`/test-mailman.py 2>&1
diff -pruN 1:2.1.29-1/debian/tests/testlib_httpd.py 1:2.1.29-1ubuntu3/debian/tests/testlib_httpd.py
--- 1:2.1.29-1/debian/tests/testlib_httpd.py	2018-06-23 13:14:21.000000000 +0000
+++ 1:2.1.29-1ubuntu3/debian/tests/testlib_httpd.py	2020-03-19 10:06:39.000000000 +0000
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 #
 #    testlib_httpd.py quality assurance test script
 #    Copyright (C) 2008-2013 Canonical Ltd.
diff -pruN 1:2.1.29-1/debian/tests/test-mailman.py 1:2.1.29-1ubuntu3/debian/tests/test-mailman.py
--- 1:2.1.29-1/debian/tests/test-mailman.py	2018-06-23 13:14:21.000000000 +0000
+++ 1:2.1.29-1ubuntu3/debian/tests/test-mailman.py	2020-03-19 10:06:46.000000000 +0000
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 #
 #    test-mailman.py quality assurance test script for mailman
 #    Copyright (C) 2010 Canonical Ltd.