V3.0 -(software) Interaction Matrix and Envelope Training for triggering, Multiple, Alternating and Velocity Shift modes now incorporate 4 notes, Alternate and Random 8 Modes, Hatnote Mode (9 note hi-hat mode w/hatKAT pedal), Link Mode (2 pads can be linked together).
V3.5 - (software) Katalyze MIDI In, 1-4 note selectable polyphony per pad, Melodic Modes, Transpose Mode, Freeze Base for Alternate pads, Ready-Record for motifs, Global & Individual Motif Protect, Song Select per kit, hi-hat control input Chick and Controller 4
V3.7/3.8 -(software) Additional Control Screens include Program & Bank Change, Kit Change and Tempo Change, Latch Mode (loops on/off), Enable/Disable for Bank Switches in Demo kits and a Bank Change for each of the six Program Changes can now be set.
This is to upgrade your DrumKAT from a 2.5 to a 3.8. This includes the upgrade chip and instructions on how to change your chip. The drumKAT manual can be found here.