Upgrading VIO 2.0 to 3.0

Hi there.

We have here at our datacenter a VIO 2.0 infrastructure with about 60 running VMs.

Of course, we're thinking about upgrading it from 2.0 to 3.0. But we have concerns in case any problems appear during the upgrade.

So I have a couple (maybe more) of questions:

1 - I saw there was a 2.5 version. Should I upgrade directly to 3.0 or should I go first to 2.5?

2 - In case any errors occur during the upgrade, is there a rollback option?

3 - My horizon dashboard is all customized (different logos, colors and a background). If I upgrade, my dashboard goes back to the default?

Any help is appreciated .