Can I edit a job using an earlier CYPE program version than the one with which the job was created or edited?

No. You cannot open a job with an earlier program version than the one used to create it or simply open it.

Should you ever wish to install two different versions of CYPE software, before editing a job with a newer version than the one it was created with, make a backup copy of that job with the earlier version. This way, you will be able to edit and work with the copy in the newer version and will have the original for the earlier version.