The following email is received from the Plesk server every hour:
Cron <[email protected]> /opt/psa/admin/bin/php -dauto_prepend_file=sdk.php '/opt/psa/admin/plib/modules/letsencrypt/scripts/keep-secured.php' > /dev/null
ERR [panel] Protocol version '22.214.171.124' is deprecated. Current protocol version is '126.96.36.199'.
#EXTLETSENC-945 "The extension no longer sends repetitive email notifications about usage of the deprecated API protocol."
- Let’s Encrypt 2.12.3 24 November 2020
If update is not possible for some reason you may try the following