Epicor Version Upgrade with QuickShip and/or CreditCard (CRE)?

Epicor ERP 10
1

We are planning to upgrade from 10.2.400.9 to 10.2.700. Would like to know what should the order of upgrade be, given we have to update our QuickShip Pro and also have CRE. Basic Questions:

  1. Should QSPro be upgraded first and then Epicor?
  2. Could we do a version update to 700 for Epicor in PILOT account only. Then version upgrade for CRE and QuickShip to work with the .700 without breaking running of the older versions of both QuickShip & CRE on LIVE (older version of Epicor lets say .400)?

Any help in what should the upgrade flow be with 3rd party services OR steps that someone has gone through going upto 10.2.700 would be great!
Thanks!