Can we connect v3 with android application.if yes then how?

[QMcKay]

SambaPOS run on Windows only. You can use mobile devices connected to a Windows computer via RDP.

SambaPOS Server, Workstation & RDP Setup Guide

This guide I wrote a while ago is based on SambaPOS V3.0.24, but is applicable to V4. It is still in draft, but covers Server setup Terminal setup RDP setup Printer setup SambaPOS Server Setup Guide (DRAFT) v2.pdf (5.1 MB)