Can QF Agent 9 run sessions created in QF8? If so are there any issues to be aware of?
Quick Fields 9 will automatically update session files coming from version 8 when they're first open. There are no known issues with Quick Fields Agent 9 running sessions from Quick Fields 8.
Without the error message, it is hard to say if your customer's issue was related to the upgrade. Was there a support case for it?
This is an interesting question.
Are you saying you do not want to open up QF 8 sessions and save them again in QF9 so they are newer versions?
From my experience, I've had no troubles taking sessions I created in QF8 and opening them in QF9 and they work perfectly. If doing this and saving them over themselves is not an option, then you will need to wait for someone from Laserfiche to respond to this question.
EDIT: Also, If it works inside QF9 then it should work with Quick Fields Agent 9
The client in mind is running QF8 Agent and has QF8 sessions. They tried upgrading to QF9 but had an issue with one of the sessions so they have rolled back (I don't know what the issue was exactly but their call was to play safe with the QF8). They are now having issues with QF8 Agent so I just wanted to keep the option of upgrading just the QF Agent to version 9.