Check this list after you migrate you database.
In Sybase IQ 15, the character encoding specification for the EUC–TAIWAN collation now uses the EUC_TW character set. You must re-create indexes on data in version 12.7 or earlier databases that use the EUC_TAIWAN collation to make them work with Sybase IQ 15.
Compare your existing params.cfg files with the new default.cfg file created by the installation. The installation does not update or overwrite existing params.cfg files. In each params.cfg file, update parameter defaults that differ from those in the default.cfg file, while maintaining any customized parameter settings appropriate for your system. Add any new start–up parameters in default.cfg to your params.cfg file. The -gl parameter, for example, is required for server start–up in version 12.5 and later.
Sybase IQ preserves the settings of all 12.7 database options that are still valid in Sybase IQ 15 in migrated databases. Check for deprecated features.
Back up your databases again with the BACKUP statement. If you use the Sybase IQ BACKUP statement instead of a system–level backup, you can run backups and queries concurrently. For complete syntax, see System Administration Guide: Volume 1 > Data Backup, Recovery, and Archiving.
For a multiplex migration, back up only the coordinator only in this manner. For secondary servers, run the dbbackup utility from the secondary server directory.