I have been excited for 4.x as it fixes known issues with products I own. Per this post by @alzhao from last January, 4.x should have been out 6 months ago.
I’m not holding my breath for a fully working release of 4.x to get out anytime soon, especially since the newly released 3.11 firmware broke the Ethernet port on the N300, which I also own, due to code changes that did not get properly tested before it was released.
There seems to be too many products for the number of engineers at GL iNet to get us working firmware, for all supported products, in a reasonable time frame.