How long will the upgrade take?
This depends on the size of the data being moved. You will be receive an email at the start and end of the upgrade process for each domain name affected.
Will there be any downtime?
There is not expected to be any downtime.
Will anything change in how I manage my cPanel account in the console?
Nothing will change except the cpanel login password is no longer viewable for security reasons. If you need to change your password, you'll be required to change your password via the console.
I have a WHM account, will you be updating the DNS for the sub accounts?
If the WHM end user DNS is using the cPanel WHM nameservers (ns-1.ezyreg.com and ns-2.ezyreg.com) then we will update the DNS. For domains using any other DNS including TPP Anycast DNS, you will need to update the DNS for these customers. DNS records will be provided to you upon completion of the upgrade.
Is there anything I need to do in preparation?
We strongly recommend lowering the TTL to 300 for all affected DNS records as soon as possible to minimise any downtime, for more information check out Understanding TTL Values In DNS Records.