[#1642] Remove outdated extension ZIP packages
[#1623] Improved error handling when starting extensions using systemd
[#1619] Reduce provisioning time of some custom images
[#1617] Improve the handling of extension download errors
[#1634, #1640] New API for extension authors to handle errors during extension update
[#1606] Fix handling of errors in calls to openssl
[#1599] Improve logic to determine current distro
[#1567, #1614] Reduce verbosity of several logging statements
Bug fixes: [#1506 #1563 #1568 #1570 #1572 #1573 #1576 #1580 #1583 #1595 #1600 #1606 #1607 #1616 #1625 #1628 #1630 #1641 #1644 #1655 #1664 #1666]