Comment 16 for bug 1604128

root@maas:~# dpkg -l | egrep 'python3.5|maas'
ii libpython3.5:amd64 3.5.2-2~16.01 amd64 Shared Python runtime library (version 3.5)
ii libpython3.5-minimal:amd64 3.5.2-2~16.01 amd64 Minimal subset of the Python language (version 3.5)
ii libpython3.5-stdlib:amd64 3.5.2-2~16.01 amd64 Interactive high-level object-oriented language (standard library, version 3.5)
ii maas 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all "Metal as a Service" is a physical cloud and IPAM
ii maas-cli 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all MAAS client and command-line interface
rc maas-cluster-controller 1.9.4+bzr4592-0ubuntu1~14.04.1 all MAAS server cluster controller
ii maas-common 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all MAAS server common files
ii maas-dhcp 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all MAAS DHCP server
ii maas-dns 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all MAAS DNS server
ii maas-proxy 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all MAAS Caching Proxy
ii maas-rack-controller 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all Rack Controller for MAAS
ii maas-region-api 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all Region controller API service for MAAS
ii maas-region-controller 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all Region Controller for MAAS
rc maas-region-controller-min 1.9.4+bzr4592-0ubuntu1~14.04.1 all MAAS Server minimum region controller
ii python3-django-maas 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all MAAS server Django web framework (Python 3)
ii python3-maas-client 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all MAAS python API client (Python 3)
ii python3-maas-provisioningserver 2.0.0~rc2+bzr5156-0ubuntu1~16.04.2 all MAAS server provisioning libraries (Python 3)
ii python3.5 3.5.2-2~16.01 amd64 Interactive high-level object-oriented language (version 3.5)
ii python3.5-minimal 3.5.2-2~16.01 amd64 Minimal subset of the Python language (version 3.5)

this machine went through do-release-upgrade from trusty to xenial after a fresh MAAS installation on 14.04 boot media.