Hello Aaimir,
Best practice solution.
1. Stand up a test environment. Move your production system there. Test the upgrade to the current release. Confirm everything works.
And when it does BUILD A RUN SHEET.
1.5 Repeat as needed on test.
Production system runs and keeps accumulating new tickets.
2. At the time of upgrading production, backup everything. Preferably with virtual machine snapshots. Implement your runsheet against production.
You should NOT as a best practice solution be thinking of partial table loads. You'll get yourself into a tangle there.
To be clear, it can be done. But it requires an experienced set of hands that knows exactly what to extract, to remap and to reload. This is a CA Services or CA Business Partner engagement and would need to be carefully checked. It is only used when the circumstances dictate it is the best solution.
I'll echo Jon's advice. Please have a look at the above recommendation and build around a run sheet and upgrade scenario. Not against a data load scenario.
Having said that, you may possible be able to Archive and Purge everything EXCEPT your production data that has changed. Then upgrade the test system again to the new release. Then do data extracts and data loads on the same version. It would be cleaner than moving data between versions. But again, this is a case that you'd want to really know what you're doing, and I'd recommend getting some help in. Otherwise you run the risk of taking tickets but not activity logs, or something similar, and it could get real messy real fast.
Thanks, Kyle_R./