[Same response I gave to this version of your question in the SAP Apps on ASE group]
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If you're changing the dataserver page size (eg, 2KB to 4KB), the default sort order, or possibly the default character set, then the 'easiest' method will be to create your ASE 16 tables, bcp the data, add your constraints and indexes (plus views, procs, triggers, permissions, etc). You can look at using ddlgen (comes with ASE) for reverse engineering your DDL.
If you're sticking with the same dataserver page size, same sort order and same/comparable character set, then doing a dump-n-load should be sufficient (this would fall under the heading of 'cross platform dump and load'; see the install/upgrade manuals for details).
Migrating your logins and roles should be relatively easy via bcp's (though you'll need to check the structure of the syslogins/sysloginroles tables for any new/changed columns in ASE 16 ... and if such exists, you'll likely need to bcp the ASE 15 data into an intermediate table (eg, in tempdb) and then perform the appropriate insert/selects to get the data into syslogins/sysloginroles.