Update 1.2.6 released

This is a service and security update to the stable version 1.2. It contains some important bug fixes and improvements which we picked from the upstream branch.

See the full changelog in the release notes on the Github download page.

This release is considered stable and we recommend to update all productive 1.2.x installations of Roundcube with this version. Download it from roundcube.net.

Please do backup your data before updating!