You can upgrade manually without using a wizard or utility.
To upgrade Adaptive Server manually, use the upgrade executable located in the $SYBASE/ASE-15_7/upgrade/. 
 
- Shut down the pre-15.x server.
 
- Copy the server entry from the old interfaces file
to the new interfaces file.
 
- Copy the server_name.cfg file
from old directory to the new $SYBASE directory.
 
- Start the 15.7 server with the old master device from the old server.
 
- Run upgrade. If problems occur, fix
them, and  re-run the upgrade process.
 
- Reinstall the Sybase-supplied stored procedures to prevent
any errors caused from changes to the  system catalogs.