All existing data is retained during the upgrade process.
To upgrade please run:
yum install letsencrypt-cpanel
If you are not getting a new version, you may need to first run:
yum clean all
Please note, as per the WHM configuration in Home >> Server Configuration >> Update Preferences, the Let’s Encrypt for cPanel plugin will be automatically updated if the ‘Operating System Packages Updates’ option is set to ‘Automatic’.
More information on this option can be found here.