This firmware upgrade chip will provide access to the latest performance features introduced in the trapKAT 6, and contains 24 pre-set User Kits that will be retained when the instrument is reinitialized.
I bought this new for $99.00 about a year ago to upgrade from v4 but, after trying it out, decided I didn't need any of the added features and preferred the simpler layout over this one.
More details here:
https://alternatemode.com/products/trapkat-6-0-firmware-upgrade-chip