Can you mix TP-Link Deco S7 and TP-Link Deco M4

I have a 2 x deco M4R(EU) Ver:2.0 and 1 x M4(EU) Ver:4.0, the Ver 4.0 does not pick up clients even if it has a strong signal and the phone is next to it. I rebooted the deco a couple of times but no...