The main reason for a major release jump is a major update of the underlying Linux environment, OpenEmbedded, and not related at all to Enigma functionality (which is just an application).
There are several parts of the image that are the responsibility of the manufcaturer, for the simply reason they can't or won't supply the source code of something as open source.
That inlcudes all hardware drivers (the source is under NDA from the SoC manufacturer), and commercially licensed products like HbbTV (for example the Opera HbbTV SDK).
This means that if the manufacturer isn't bothered to upgrade their applications to work with a new operating system version because it has a cost and you've already bought the box, you have a problem.
This is made worse by another image often used by those that can't even be bothered making their own image, which isn't that bothered with legalities. They for example "stole" one vendors' HbbTV solution and hacked it to work for other brands.
OpenPLi doesn't do that. If a vendor wants to provide its users with HbbTV, they will have to. And not like VU+ do it once, many years ago, and then forget about it. They would respond "use OpenVuPlus, it hasn't had an OE update since ever, so for us it works".
Bottom line, you're being shafted by the manufacturer (not unlike smart TV's that are not that smart anymore after a few years), nothing OpenPLi can do about it.