We have done a workaround and our clients are using Roundcube 1.4 already since it's out. I please all others in the thread to do a bit more work themselves instead of spamming Plesk that they should implement it.
Plesk Obsidian 18.0.26 now available:
Updated Roundcube to version 1.4.3. The “Elastic” responsive skin with full mobile device support is now enabled by default.
We have done a workaround and our clients are using Roundcube 1.4 already since it's out. I please all others in the thread to do a bit more work themselves instead of spamming Plesk that they should implement it.
i think the reason is that onyx only gets security-related patches.
Plesk Onyx End of Extended Support October 11, 2020
In terms of Plesk Onyx, Extended Support is a 4-year period, after which the product will no longer be available for new purchases and will only receive patches for critical issues. The Extended Support Period is six (6) months.