You need to have the Message Server running to provide real time updates.
On your computer that you use as a Server, run Samba.MessagingServerServiceTool.exe that is in either
C:\Program Files (x86)\SambaPOS4\ or C:\Program Files\SambaPOS4\
Set the Port number to 8383 (so it doesn’t conflict with other services), and click Install Service, then click Start.
NOTE: You only need the Message Server running on 1 computer ONLY.
Go to SambaPOS, Settings->Local Settings
Set the Message Server Name to the Computer Name that you installed the Message Server on, set the Message Server Port to 8383, tick Auto Start Message Client.
Click Save, exit and restart SambaPOS.
If you have set it up correctly, you should have a green Connected on the bottom of the SambaPOS screen.