New build available for download
The new build for UE4 4.8.* is available for download on Sellfy! As always, it’s free for existing customers. For those who’ve missed the build notes, here they are.
I haven’t had any problems using PHP for the login system so I don’t see the need to switch to a socket server. I’m using a socket server for chat though.
Yeah I’ve thought about it. It’s kinda easy to implement yourself though, and I was trying to focus on more difficult stuff - inventory/equipment/quests as some of my priorities. Now that those are out of the way, I will probably add a hotbar soon.
They are not accepting assets that contain code to the Marketplace yet. Regarding “surety”, Sellfy has been around for more than 2 years now, and that’s longer than UE4 Marketplace. 
I haven’t implemented instancing yet but it shouldn’t be very hard to do. You could modify the chat server source code to send a command that would tell the server to launch a new instance. The server would then send back the newly created instance’s port so that the client knows where to connect. Then on the client just use the Load Level blueprint node with the server ip and the received port.