Upgrade from 2.0.3.1 to 3.?? - advice wanted on how & which version

I'm looking to upgrade from 2.0.3.1 to the latest OC3 and would appreaciate advice from the forum:

1) which version should I upgrade to 3.0.2.0? 3.0.2.1b? something else?

2) where can i find some help on the upgrade steps?

3) is there a migration tool?

Thanks in advance

1) which version should I upgrade to 3.0.2.0? 3.0.2.1b? something else?

2) where can i find some help on the upgrade steps?

3) is there a migration tool?

1 - Latest release, always.
2 - If you do not know how to upgrade your store, seek help from a professional to do it.
3 - Extend the PHP Maximum Limit to your server and run an upgrade from the install folder by first making a full backup of your store and its database. You can also look at the marketplace for upgrade tools.