Hi there,
I am looking at moving onto the new chat system made by Roblox, but before I make this move, I am looking at the new way to make a system chat message. Currently, I have in-game chat tags sorted, but how do I make chat messages?
This is how I used to do it, but this no longer works:
game.StarterGui:SetCore( "ChatMakeSystemMessage", { Text = "Welcome!", Color = Color3.fromRGB( 255,0,0 ), Font = Enum.Font.Arial } )
Currently in the process of updating my chat also
game.TextChatService.TextChannels.RBXGeneral:DisplaySystemMessage(Message)
Thank you so much!! Curious, where did you find this? I wasn’t able to find documentation?
Took me a bit to figure it out but I found the :DisplaySystemMessage() event in the documentation link. Didn’t know exactly what to call it on but after a bit I figured out you just call it on one of the TextChannels in the TextChannels folder which is under the TextChatService in explorer. There’s 2 TextChannels that roblox makes when the CreateDefaultTextChannels property is enabled under TextChatService, RBXGeneral and RBXSystem.
About to try to set up some chat tags for Owner, V.I.P, etc. Wish me luck lol
Ah, okay, thank you very much! 
I figured out color using roblox’s HTML Mimic by using
game.TextChatService.TextChannels.RBXSystem:DisplaySystemMessage("<font color=\"rgb(255, 0, 0)\">Hello world!</font> ")
I am sure this has already been figured out by now but for anyone who doesn’t, this is how.
Awesome! Thanks, it’s very helpful!
Glad I could help. Took me a bit to figure this out 
Is there any way to run this on the server side?
Based on what I can tell. No, You would be better off using a remote if you want to display a message to all clients. Like shown here:
-- Client
Remote.OnClientEvent:Connect(function(Message: string)
game.TextChatService.TextChannels.RBXGeneral:DisplaySystemMessage(Message)
end)
-- Server
Remote:FireAllClients(Player, Message)
Do you happen to know how to edit the font type? I’ve been trying to look for an answer but to no avail.
<font face="Michroma">This is Michroma face.</font>
game.TextChatService.TextChannels.RBXSystem:DisplaySystemMessage("<font face="Michroma" color=\"rgb(255, 0, 0)\">Hello world!</font> ")
Thank you! It works!
Minimum chars