@Naif1981 

The downgrading procedure is the same as upgrading procedure (Case 1 for manual upgrade) - just using an older FW release.

If you're with the US versoion of the FW here are the release notes for the version you are with.

Pay attention to the Note at the end of the release notes:

@Naif1981 

TBH, not that I know of. You may contact your local support, state your issue and ask them for assistance.

Naif1981 wrote

@terziyski I am on the US version. And what I understand that I won't be able to downgrade using the normal process. Is there another process? I have bought the router to use L2TP protocols and now for some reasons it's not working with it and keep on disconnecting and lose the connection.

so any thoughts how to downgrade? 

@Naif1981 

Can you describe the issue in detail? Do you mean you are using the L2TP VPN Client connection on the router but it is not connecting? What kind of VPN server you are connecting to?

You can follow the thread to see if you can get it resolved:

https://community.tp-link.com/en/home/forum/topic/270268

Naif1981 wrote

@Kevin_Z yes exactly. I am using L2TP on the router and it keeps disconnecting. I have to change server address so it connects again, but that won't last for more than a couple of minutes. 
thanks for the help...

@ic3b34r Thank you for providing the valued information. That really gives us some highlights.

@Naif1981 so can you confirm if you could still connect to the L2TP VPN server on the computer or phone directly when running a VPN Client software? If that still works, we would like to escalate the case to the support engineers for follow-up. They would contact you via your registered email address in the community.

@Naif1981 

Got you. I found you have already opened a support ticket, and the support engineers will contact you soon, please check and wait.