What does the Keep websites secured option for SSL certificates in Plesk do?

Question

• What does the Keep websites secured (aka Keep websites secured with free SSL/TLS certificates) option for SSL certificates do on a Plesk server?
• Will the SSL certificates that have been issued for domains already keep getting renewed if the Keep websites secured (aka Keep websites secured with free SSL/TLS certificates) is turned off for my Domain, Subscription or Service Plan?

Answer

The purpose of the Keep websites secured (aka Keep websites secured with free SSL/TLS certificates) feature is to forcefully and regularly try to issue new free Let's Encrypt certificates for domains, subdomains, domain aliases, and webmail that do not have any issued already in order for them to become accessible via HTTPS instead of HTTP.

Domains that have Let's Encrypt certificates issued before manually will be renewed automatically, even if the Keep websites secured option is disabled for them.

Due to this, the Keep websites secured is disabled by default and must be turned on manually for an entire Service Plan, Subscription or Domain in Plesk.

Additional information

Securing Connections with the SSL It! Extension | Plesk Obsidian documentation