If you have mobile applications that use a custom SAP result checker, you must upgrade those applications to use JCo version 3, before you upgrade production servers to Sybase Unwired Platform 2.1.
Any package that uses custom SAP result checkers with JCo prior to version 3 is disabled when you upgrade to Unwired Platform 2.1. To reenable a disabled package, see Enabling and Disabling a Package in Sybase Control Center for Sybase Unwired Platform.