Is it okay to downgrade to version 2.2.5?

I have two installations that are suffering from this issue.  No one can access FQDN's.  Browsing fails for everybody!

Disregard my issue but I have to warn ER605 users about this issue.  I have downgraded to firmware version 2.2.5 and it fixed my LAN devices' DNS resolution issue.

ER605 V2 firmware version 2.2.6 is blocking DNS requests from LAN devices!!!!

  @firefox111 

Weird, I don't have such issue, and I'm using 2.2.6 on my ER605 v.2 for 6 months now.

  @RaRu 

This version was released last December! My wife noticed this yesterday because our smart TV wasn't connecting to the internet. Our iPad's and computers didn't experienced this because ExpressVPN is in our devices, not on TV's. So, when I disabled ExpressVPN from my PC, that's when I acknowledged that there was a problem! No matter what I did - manually entered the Primary and Secondary DNS on my PC, DNS queries don't get resolved.

Late last night, I rolled back to version 2.2.5 and everything got resolved. It was weird because the Diagnostics in the ER605 was able to resolve DNS yet it is NOT letting LAN devices resolve DNS!

Oh, I forgot to mention that I have two locations connected using site-to-site VPN and both experienced the same problem! Also, in both of my ER605's all items in the "Attack defense" in Firewall are all checked. Is yours all checked?

My conclusion is, TP-Link is releasing firmware publicly without thorough testing??? Maybe???