Just bought the MR200 from Cosmote rep in Greece. The router was V4 with some initial firmware revision dated 14/08/2019. This is 2 years ago. Current release for MR200 is V5 and V2 for firmware. TPlink is rushing in releasing products and stepping on their toes making one mistake after another. The MR200 V4, I have no idea what happened before V4, is by no means a mature ready to go and obviously was released prematurely.  Tried to configure it and based on invluded instructionsThe password was the one on the back of the router and not the "admin" stated in the manual. Typical for products that are rushed to market. I configured the product the same way to my existing Huawei router so when I turn off the old one and on the new one things need to work. Not exactly , the 5Ghz band came up and connected all devices but the 2.4Ghz band has protocol violations and not connecting.. I have a bunch of devices cameras and switches and smart plugs etc that didn't connect to the 2.4Ghz band. I tried to connect my iphone 10 and my wife's 12 on 2.4Ghz and didn't not connect. Well Apple is the gold standard for any band so sure enough TPLink messed up somewhere in the implementation. So I thought maybe a firmware update could fix this issue since the f/w on the MR200 was prehistoric (2years for firmware is considered centuries!). I found the Firmware for V4 with a date Feb 1st 2021. That is pretty good and could really solve some problems. Here is were Cosmotes wisdom shines , they locked the router so it takes no Firmware updates. Brilliant Cosmote, what were you thinking ? Now you have a bunch of customers with issues that nobody can fix so they are stuck with a defective product. Some brilliant marketing guy probably suggested why don't we prevent all our customers from moving to our competition and take the hardware with them. Well in the expense of their customer satisfaction their are blocking their customers for fully utilizing their hardware by updating to the improvements from the supplier, that is TPlink. When you try to update the router gives you a 4503 error , no you just can't do and update and fix your issues , we will keep you in the dark ages.. Very short sighted  for both Cosmote and TP-link. This could be illegal for cosmote but the laws may be different. Do yourself a favor and buy an "unlocked" router not from your carrier but from the open market. They could be cheaper too so you can upgrade them until some maturity kicks in..The MR600 maybe the choice and TP-link should retire the MR200 for sure , the MR400 could be an alternative. I did ran a speed test and Huawei beat the MR200, the version I had by 30% , not surprised as I determine that they can't lock on B7 band successfully so they start degrading the speed. That is another story all together.