Following the scheduled migration weekend, you will need to regenerate the API keys again and also pass in accountId instead of UserKey in the JWT Token.
zfj-cloud-rest-client-1.2-jar-with-dependencies.jar should only be used by customer who has received the scheduled migration email. The artifact can be updated after the scheduled downtime is over.
For all other customers who have not recevied scheduled migration email should continue to use the old artifact (zfj-cloud-rest-client-1.1-jar-with-dependencies.jar) until you receive the scheduled migration email.