An upgrade is not optional - it is the only solution.
You can run the automated conversion quite safely.
If your Anti-virus comes up with an issue - We have tested this on all Antivirus programs (Some of them show malware as 4POS now needs to register new DLL's - this is required for new processes to open cash drawers and / or pole display...)
If your Anti-virus program does not allow the installation or creates a problem, simply disable the Anti-virus for an hour or till you restart, so you can proceed.