Hope this version can be tested and implemented soon in Nethserver 7.
As mentioned on the Roundcube website:
We proudly announce the final release of the next major version 1.5 of Roundcube webmail. With this milestone we introduce new features and full PHP 8.0 support. The most noteworthy additions are:
- Dark mode for Elastic skin
- OAuth2/XOauth support (with plugin hooks)
- Collected recipients and trusted senders
- Moving recipients between inputs with drag & drop
- Full unicode support with MySQL database
- Support of IMAP LITERAL- extension RFC 7888
- Support of RFC 2231 encoded names
- Cache refactoring
See the full changelog in the release notes on the Github download page.