Question
Does Plesk service (sw-cp-server) support the version 1.3 of the TLS protocol on Linux server?
Answer
The support of TLSv1.3 has been implemented in Plesk Obsidian and is available only for RHEL 8, CentOS 8, Ubuntu 18.04, Ubuntu 20.04 and Debian 10 since this protocol requires the version 1.1.1 of OpenSSL, available on official repositories of the aforementioned OSes only. Also, TLSv1.3 support is enabled by default on all new installations on these OSes.
To enable TLSv1.3 for sw-cp-server
service follow the instructions from the article How to enable or disable TLS protocol versions in Plesk for Linux?
Note: Plesk Onyx does not support TLS version 1.3, and its support is not planned to be implemented.