I have the Deco M9 Plus with hardware v2.8.  Typical 2 unit setup with 1 being the main and they are working fine.  I am actually quite happy with the product and how it performs.  I use my Deco App everyday to control my smart devices and that works great too. 

One thing I have noticed is that there has not been any firmware updates since 2019 (based on the firmware version # reported thru the Deco App).  I got curious and checked the TP-Link Support site.  It does confirm hardware v2.8 hasn't has any firmware updates since 2019.  BUT I noticed hardware v2 has regular updates with the latest firmware released in 2022 Jan!  

How come the latest and greatest hardware version (I would that v2.8 being the highest # is the latest revision) is not being supported with firmware improvements?

When will the firmware improvements ported over to hardware v2.8?

As an owner of the system, I would like to take advantage of the latest development and/or bug fixes.  In fact, i would expect all the improvements are ported across all the different hardware versions of the same system but that is not the case.  How come?