v0.53 (April 12, 2021)
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Software updates:
* Upgraded Roundcube to version 1.4.11 addressing a security issue, and
its desktop notifications plugin.
* Upgraded Z-Push (for Exchange/ActiveSync) to version 2.6.2.
Control panel:
* Backblaze B2 is now a supported backup protocol.
* Fixed an issue in the daily mail reports.
* Sort the Custom DNS by zone and qname, and add an option to go back to
the old sort order (creation order).
Mail:
* Enable sending DMARC failure reports to senders that request them.
Setup:
* Fixed error when upgrading from Nextcloud 13.
8993ebd3a8