Question: I moved my application from one.example.com to two.example.com. Do I need to get a new set of application keys (DevID, AppID, CertID)?
Answer: No. Although web service APIs offered by other companies require you to obtain a new application key when moving to a new server, this is not the case for eBay web service APIs.
Note, however, there are different keysets when requesting services from eBay's sandbox or production environment.