Released on April 9th, 2019md5sum
The list of major changes is described on Piwigo 2.9.0 release note
Piwigo 2.9 fails with Piwigo Remote Sync
strpos() is deprecated in php 7.3
[albums] performance issue on edition page, when too many photos
Wrong handling of strange section fields in pwg_log
pwg_log is not checking if given $page['section'] is part of the enum in the table
[2.9.4] users list no longer paginated or filtered
French Canadian (Québecois)
Hong-Kong Chinese (中文香港)
We recommend the automatic upgrade. If you're running version 2.2+, Piwigo will tell you which plugins may be not compatible with Piwigo 2.9 before upgrade.
If you're running Piwigo 2.9.x you can also download the 2.9.x_to_2.9.5.zip archive that contains all new and modified files. Once you have extracted the files, transfer them onto your web server with a FTP client over your Piwigo 2.9.x installation. No database upgrade is required.
If you are running a version older than 2.9 and do not want to use the automatic upgrade, then follow the manual upgrade.