In case of the Polysix, the Kiwisix upgrade serves two purposes. Firstly, it repleces the original CPU (processor) board that is almost alywas a victim of the acid spill from the infamous, bright blue Varta battery.

 
Secondly, the KiwiSix Upgrade features:

•A complete replacement board for the troubled Korg Polysix KLM-367 circuit board. These are usually battery damaged which can be difficult and expensive to repair and render the synth unusable.

•1024 Tones can be stored and edited. It is also possible to temporarily edit any Tone. Tones are selected using a two button system. The first button selects the high digit (bank 1-8) and the second button the low digit (Tone 1-8). This allows 64 tones (1-1 to 8-8) on any bank group. There are 16 bank groups that are selected using the A-D bank buttons.

•MidiCC and Sysex support all parameters. Sysex support for Tone Dump & Load and 4096 step parameter control.

•NRPN support on all variable controls giving 4096 step control.

•4096 step scanning on all front panel controls. Optional Fine midi control using sysex or NRPN (v1.20+) on all variable controls.

•Midi In & Out Channels can be separately set.•Patch Editor Control of Parameters (requires PE v 5.0 or later)•Two styles of Polyphonic (7th note override or 7th note ignored) and Last note priority Unison Key Assign Modes.

•Chord Mode. Any chord with up to 6 notes can be set and played from any key.

•The Arpeggiator can be clocked from the internal/external clock or midi clock divided by 3, 4, 6, 9, 12, 18, 24, 36, 48, 72, 96, 128, 144, 168 or 192.•Arp modes are Up, Down, Up and Down, Random (midi only), 0, 1 or 2 octaves and can be controlled via midi.

•Key transpose allows transposition to any key in a range of 2 Octaves up to 1 Octave down.

•Arpeggiator can be Started, Stopped & Continued using Midi Commands.

•Appeggiator will Output Midi Data.

•Internet update system. All future updates will be at no charge.

•The Upgrade comes with a replacement metal plate for the power cord. This plate has an IEC socket for a standard power cord (note that ower cord is not supplied), screws and space to mount the Korg Serial Number plate and midi in and out sockets are mounted. An internal cable is supplied to plug into the KiwiSix Upgrade board for Midi I/O.