If they said free updates till 4.2 and now are going back on their word...
They can't expect people not to complain
Well, they could have simply named it 4.2 instead of 4.17 and stated that mesa and multicore support would be added in update 4.21.They could also charge again for 4.21 since they have made no promises regarding 4.2's pricing structure.
I prefer that they called it 4.17, and have lowered the price as a concession. Seems fair.