Re: X-Cart become subscription based, so what should I do?
There is no more XC4. They stopped selling XC4 licenses long time ago or at least were phasing them out.
The free/discounted XC4 to XC5 license is gone (it was $49). It's been at least 2 weeks now.
The yearly "access fee" upgrade of $195/year and "late" upgrade fee of $350/year is gone. It's been at least 2 weeks now.
The only thing you can purchase right now is Enterprise for $199/month or $1910/year. And with this I assume the cart will stop working if subscription is not paid.
Existing XC5 licenses prior to this are lifetime licenses and they will continue under the terms at the time they were purchased. In other words - $195 or $350 per year. That's what I know but since there is nothing from QT/SL on this it may not be the case. Lifetime XC5 licenses continue to work without paid subscription but cannot get upgrades after subscription expires.
The new Enterprise comes with some products/services that may not be suitable for all. So the possibility is most new XC5 users will pay more than they should because of these unusable to them products/services. Not all want to use XPayments. In fact I think they have bundled X-Payments and ClourSearch into this because they don't get enough signups for these services and it cost a lot to develop/support them.
We don't know what the "60+ modules for scaling your business;" are. I would say even if these 60+ modules are all paid modules typical cart will use maybe 5-10 of them. So for the rest they are paying for something they don't need/use.
All this adds up.