This change is unrelated to the licensing issue. It's on my own request, as the 384 series of firmware were an absolute nightmare for me to manage with all of these mismatched GPL versions, where sometimes I needed to kludge things within the code itself just to make them all work together. Some models needed to use a different model table because their binary blobs were compiled with a different version of that table. So at one point I had to create a spreadsheet to track which model was using which GPL version of the binary blobs.There seems to have been a policy change around the time that Asus / Trend Micro / Broadcom [???] raised the red flag over serious abuse of their IP by those who were flashing non-Asus routers with modified Asus/RMerlin firmware. RMerlin's Alpha offerings were, at that time, based on Asus GPL versions numbers not seen as released yet for any router models.
Firmware/GPL matrix
docs.google.com
Often, I was unable to release firmware builds for some of the models, as their older binary blobs were no longer compatible with newer GPL source code. The RT-AX88U had to be compiled from a different code branch (which I had to maintain separately, basically having me maintain two different code bases at the same time).
So before going to 386 I asked Asus that in the future, they provided me with GPL archives that were all based on the same version, to ensure complete compatibility between the source code and the closed source components. Otherwise, I was on the verge of burning out, and dropping the whole project as no longer sustainable for a single developer.
As to whether I get these GPLs based on an official release or not, it depends at which point in time I ask them for GPL archives. The 48966 code I am currently working has been used by them in the past few days for a few model releases.