@Tompabomp I have cable (coaxial) Internet and when similar thing happened, after extensive troubleshooting ISP Tech Support have found the issue to be cable with cracked insulation outside of my...

@stavrov The best option would be to have Ethernet cables between floors and connect Satellite Deco to each other and to Main Deco using Ethernet cables, like this: If you can do that, WiFi on each...

@Augusto1977 You sure can. One caveat: your Deco mesh may lose some features, if they are not supported in firmware of M4 that is added to M5 Deco mesh.

@14paavang You can configure Main Network in Deco app to brodcast 5GHz only, that will force every device connect on 5GHz.

@Bjebeje Great! Will keep that solution in mind when someone else has issues with M9 Plus firmware 1.2 update. Now your Deco M9 Plus must be on firmware 1.6. You can check that in Update Deco page....

@Bjebeje Just in case, power off/on all M9 Plus and check again in Deco app. If Main Deco M9 Plus continues to stay on firmware 1.2, do the following: Promote one of updated Satellite Deco M9 Plus to...