You need to upgrade the MobiLink server to version 12 if you are using version 12 remotes.

Before using a version 12 MobiLink server, check the behavior changes to see if any affect you. See SQL Anywhere 12 - Changes and Upgrading.

Version 12 of the MobiLink server only supports version 10, 11 and 12 SQL Anywhere and UltraLite clients. If you need to support earlier clients, you should keep an earlier version of the MobiLink server for supporting them.