Your new Plesk 12 Dedicated Server will need to have the PHP.INI Timezone set for both PHP and Roundcube.
You need to edit:
nano /etc/php.ini nano /etc/psa-webmail/roundcube/php.ini
Enter/update the timezone information as below:
date.timezone = Europe/London
Use the correct region for your location.
How to: Set PHP.INI Timezone written by UKC average rating 5/5 - 1 user ratings