[Mattman86]

So out of curiosity, I plugged my S8+ into my old Lumia Display Dock. All the USBs work and the phone charges. If I plug in a USB/Ethernet dongle, the phone will even take advantage of the ethernet connection. When I plug in an HDMI cable, the phones screen is mirrored to the monitor connected.

My question is: Is there any way to force Dex through the Lumia dock?

[SpookDroid]

If you can mirror the display through HDMI on that, then you should be able to force DeX. Can't remember what the exact setting is, though, as I don't longer use an S8 but you might be able to find DeX if you search the settings. I remember there was an option where you could set which mode it would 'kick into' when it detects an external display.

[Mattman86]

I thought there was too. But all I'm seeing in my searches is how to do it with a rooted S8. My Carrier is AT&T so rooting isn't really an option.

[SpookDroid]

Aaaah, ATT version! I think someone mentioned they didn't have that but my T-Mo one did. When you connect the external display, does it give you any notification or menu on the notification bar that maybe you can use to switch to DeX? I tried it on a Tab S4, a Note 9 and an S10+ last night and they all give you the option (granted, wasn't a Microsoft dock, it was just a generic USB-C dongle, but it should still apply).