There is a whole section on migration in the reference guide that explains it all very clearly.
The only thing it doesn't mention is the Work Environment.
If you have customised your WE, then you will either have to use new default WE and add your customisation in, or use your old WE and add all of the new features in to that.
And of course you will have to start setting up new features such as modifiers in complex profiles and expressions in properties if you want to use them.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11