The mobile POS solution or app for your venture definitely has to be flexible. With the growth of business and revenue, you may have to use more devices over the years. So, having an app with support for several devices is a good idea. As for the software, a lot of businesses are relying on Cloud-based POS applications. These are flexible as opposed to OS-specific POS apps but you have to depend on internet connectivity and internet outage will mean no operation.