@David-TP I did try that but as I said: it is on that page (tplinkdeco.net) impossible to choose only my main router unit. I can only choose between x50 and x50-outdoor. I suspect that when I choose x50, the software also tries to update "Hallway" and "Speelkamer" which are another hardware revision so the update fails.

  @David-TP Hello, ist this Firmware also compatible with the EU/German X55 V1 ?

  @David-TP 

Since upgrading to this release (1.6.7) I've had huge network issues, my network uses 3x X55 plus one X50-5g, and I use main and IoT networks.   I had to remove the X50 as main as it simply could not maintain the traffic and the network became unreliable. I moved back to X55 as main on previous 1.6 (.4) firmware, this solidified things, happy days. 
 

1.6.7 was installed 4 days ago - and problems are back with devices losing connection, struggling to connect, my Home Assistant monitor recorded a significant leap in average CPU usage (since the day of the update). I have also noted that my Zigbee devices and ARLO have also become flakey (I hadn't correlated the dates until now), they all seemed to have connection issues. 
 

I was trying to work out the issues (repeaters not working?) when I noticed an ESP device log struggling to connect to my IoT network, and trying to use "hidden networks".  The Deco network channel optimisation was constantly suggesting new 2g channels. 
 

After a little research I found that EasyMesh (new in 1.6.7) creates new hidden channels, I have turned this off (as I don't need other vendors devices as access points) and observed a significant reduction in CPU usage, the wifi network appears to have stabilised, as have my Zigbee devices. 
 

It's early days, I will keep monitoring, but the EasyMesh function appears to be creating a lot of (unnecessary) extra CPU requirements, and the (WiFi and Zigbee) channels appear less congested without it.
 

  @David-TP  hi, I have recently upgrated my network from M4 to X50 (set of 3). I am having very nightmarish experience since the upgrade. The 2.4 ghz band is refusing to stabilize, there are frequent disconnections and it is not at all stable. All my IoT devices and security camera have gone for a toss after the upgrade. 
I have updated the latest firmware available through the Deco but still no respite.

request you to provide a solution at the earliest. I am using it in India so please provide a solution regarding to the DECO X50 sold in India.

Thanks in advance!!

A

  @David-TP just FYI, the EasyMesh option was defaulted to ON after the upgrade.