Just for interest's sake can anyone point to this 'promise' of a free upgrade to version 2? I bought TM1 and it played no part on my buying decision because I was not not aware of any such guarantee.

If this promise was made then IMHO his best option is to adopt the Firefox/Chrome numbering scheme: stabilise and release whatever he has now as TM2.

He should also change the licensing to free updates for 12 months from date of purchase and continue working on TM3.