TP-Link routers are now locked

It's been discussed here previously. Now I see this:

http://ml.ninux.org/pipermail/battlemesh/2016-February/004379.html

"Yes. Less than 24 hours ago I was given the following information from a
customer service rep from tplink:

Adam Longwill09:10:01 pm downgrading does not work
I get an 18005 errror
upon attempting to downgrade
I want to know if this is because of the FCC's rules regarding broadcast
strength and DFS control. Has TP-Link complied with these rules and locked
down its firmware and if so, for what models
I need to know if I am going to continue purchasing devices from you.

Camille09:13:25 pm wait one moment please
Thanks for your waiting, right now only these products has limitation on
firmware: Archer C7 V2 Archer C1900 V1 Touch P5 V1 Archer C2600 V1 Archer
C3200 V1 Archer C2 V1 Archer C5 V2 Archer C8 V1 Archer C9 V1 TL-WR841N V11
TL-WDR3500 V1 TL-WR940N V3.0 TL-WR1043ND V3.0 TL-WR710N(USA) TL-WR841N V9.0
and all products will also limite firmware in the future.

Adam Longwill09:26:19 pm Wow. Thank you. I'm impressed with your digging
And this limitation is due to FCC rule clarifications in 2015?
And not some other reason

Camille09:28:15 pm Right, due to FCC

Adam Longwill09:28:50 pm Thank you very much. Can you explain why the
WDR3600 appears to be locked down? Is it possible that your list is not
totally updated?
And do you have a method or avenue that people who wish to use other
firmware have?

Camille09:34:02 pm Yes, wdr3600 as dual band wifi router, is also locked
down. And there is no other way to use other firmware. Sorry for that

Adam Longwill09:34:19 pm Thank you very much, Camille. You've been very
helpful

Sorry for the formatting, I'm on mobile."

etc., etc., more if you click the link above.