That's from this official site ( Top most
post #1 on this P-5 / 10 forum site ....
This site you're on right now. )
Post #4 (also in blue text ) contain the "newest" manuals.
Post #1 also have instructions how to use the "newly" added features / upgrades ( aftertouch, Q-comp. and more )
Just scroll down and read
I have used 2.04 for approx a year ... No problems.
Your custom presets will be OK.
However ....
Do a backup before anything else just in case, and follow the steps in the
above mentioned
post when update OS and PANEL ....
Cheers !