You can open an Adaptive Server 15.7 SP100 database in an earlier 15.7 Adaptive Server by using the sp_downgrade_esd system procedure.
If you have a database in Adaptive Server version 15.7 SP100 that you want to open in Adaptive Server 15.7, 15.7 ESD #1, ESD #2, or ESD #3, or ESD #4, you can downgrade it with sp_downgrade_esd and perform the dump and load. You can then revert the database so that it is usable in the current version of Adaptive Server again.
Perform these steps for one database at a time, and only for the databases you want to open in an earlier version of Adaptive Server 15.7.