I am done with ASE 15 or more like follow
XP (12.5.3) --> Windows 7 (ASE 16) SKIP ASE 15 (VISTA)
I'm not in product management, so I can't give an official date, but
let's just say that skipping ASE15 and going to ASE16 from 12.5.3 would
leave you in 12.5.3 (which is entering end of life) for awhile now ...
If you could go to ASE15, even on Windows XP (or even windows server)
then from a technical support / EBF perspective you would be running a
version of ASE, for a longer period of time, that would continue to
receive product updates, etc. There's no guarantee that the migration
from 12.x to 16.x would be easy as dump and load.
Let's just say it's going to be a few years out, at the MINIMUM
-Chris