Model : TL-WR840N

Hardware Version :

Firmware Version : 0.9.1 3.16 v0001.0 Build 161011 Rel.60105n

ISP : Business Network Ltd

My Router is TL-WR840N (EU), hardware version 4.0. I searched on tp link site and found my router model, this is the link http://www.tp-link.com.bd/download/TL-WR840N.html#Firmware . But it has firmware only up to hardware version 2, while mine is version 4. Today I found another link from another post: http://www.tp-link.com/en/download/T....html#Firmware. It has update to hardware version 5, version 4 has a new release, TL-WR840N(EU)_V4_170421. But it says:

"It is NOT suggested to upgrade firmware which is not from your local TP-Link official website. Please click here to choose the purchase location for your TP-Link device and download the most suitable firmware version."

And If I chose my location, then redirects me to that old link with my country domain, where only hardware version 1 and 2 is available.

Now, should I update my firmware? I don't wan't to break my router.