@Evrard Yes, it does. Because E4 has 100Mbps Ethernet ports, its Ethernet backhaul speed will be limited by that. More info about Deco Ethernet backhaul can be found here: General questions about...

@RajatBoon Your Deco M9 Plus has old firmware. It is version 1.2.12 from 2019, three years old. The latest version is 1.5.6. When you update M9 Plus to the latest version, you'll see the option to...

@Jonathan1115 The only special case I know of is Deco WiFi 6E capable devices: AXE11000 Deco XE200/Wi-Fi 6E Deco Mesh System According to TP-Link FAQ, it appears on these devices one can create a...

@Jonathan1115 You can only have two networks with Deco X20 mesh. You can make Main Network 5GHz only and connect to Guest Network devices which can only work with 2.4GHz.

@MDXS Wired backup is better than wireless backup, in practically all home networks. You can mix wired and wireless backup. Also, see this FAQ for Deco backup (called backhaul) topics: General...

Alexandre. wrote @RajatBoon It is possible you have really old Deco M9 Plus firmware version. Please open in Deco app More/System/Update Deco and after it populates - make screenshot and share here....