Again, the only time I think it's unfair is for people who bought v4 in May, for example.
I would hope that, for a period after it was known that v4 would not support High Sierra, they were given either a refund or a free upgrade to v5.
I would hope that, for a period after it was known that v4 would not support High Sierra, they were given either a refund or a free upgrade to v5.
It keeps customers who bought just before a new release happy, and removes anxiety about whether you should wait until next release to buy.