In order to use the Newton Connection Kit with the Newton 2.x OS, you must have a newer version of the Newton Connection Utility software. Newton Connection Utility v1.0 software provides the same functionality; including backup, restoration, and importing files, as the older Newton Connection Kit.
If you chose not to upgrade to the Newton Connection Utility, there are some other alternatives from other software vendors. The article titled "Newton OS 2.0: Newton Connection Utility Alternatives" provides a list for both Macintosh and Window computers.