Hello. I have 3 unit deco S4 -  V2.0 and another 3 units S4 - V4.0 in my house connected in a mesh system. 

Very  often after opening the DECO APP it show most of the units are offline, but they actually are online. When I refresh the app the units go online again. 

All of the units are upgrade to the latest software version - The V2.0 is upgraded  to software version -   1.6.1 Build 20231228 Rel. 59072 and the V4.0 are 1.1.2 Build 20231227 Rel. 84005

Also my Decos V4.0 have the Connection preference but it does not allow me to save the desired signal source. 

The V4.0 units are connected to the mesh system after the main mesh router which is V2.0

Should I change the main router with hardware version V4.0 unit in order to allow me to chose desired source signal?