The initial update from .43 to .44 had the following issues:
~30 minutes for Nextcloud update. Just glancing at the list of tasks printed, it seems like the download is the weakest link by quite some measure. Perhaps move this to some sort of prerequisite task to be completed prior to taking down services?
The end of the update concluded with:
Installing Z-Push (Exchange/ActiveSync server)...
FAILED: apt-get -y -o Dpkg::Options::=--force-confdef -o Dpkg::Options::=--force-confnew install php-soap php-imap libawl-php php-xsl
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E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?
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I rebooted the server then ran sudo mailinabox and the setup completed without issue.