I'm curious as to why you "need" to upgrade ?
Are you missing features ?
Have you found bug that are fixed in later editions ?
Or are you just moving to the latest version ?
If you're moving to a new version, this shows the fixes that are in different releases.
Targeted ASE 16.0 Release Schedule and CR list Information - SAP ASE - SCN Wiki
There's a release coming next month so you might want to wait or at least have different version available. Personally we've found 16.0 SP02 PL02 to be unstable for us so we're waiting for the June release before fully upgrading.