FTR, I spotted a couple of things that turned out to be non-issues:
1) The letsencrypt binary has become a symlink and moved to the certbot binary package. This needs a Breaks/Replaces, which does exist but doesn't cover the version of letsencrypt currently in xenial-proposed. However this isn't a problem because the movement had happened prior to the version in xenial-proposed.
2) We're still shipping /etc/cron.d/certbot as it is in the Bionic backport source. However it is inert, as intended, since Ubuntu >= Xenial always has systemd (unless you're upgrading from Trusty but haven't rebooted yet). Even if the cron job did run, it wouldn't be a problem.
FTR, I spotted a couple of things that turned out to be non-issues:
1) The letsencrypt binary has become a symlink and moved to the certbot binary package. This needs a Breaks/Replaces, which does exist but doesn't cover the version of letsencrypt currently in xenial-proposed. However this isn't a problem because the movement had happened prior to the version in xenial-proposed.
2) We're still shipping /etc/cron.d/certbot as it is in the Bionic backport source. However it is inert, as intended, since Ubuntu >= Xenial always has systemd (unless you're upgrading from Trusty but haven't rebooted yet). Even if the cron job did run, it wouldn't be a problem.