My shop ordered several Samsung Tabs in anticipation of Shopify updating the Android POS app on May 5th. Which ended up being more like May 12th but that's a whole other post. Finally, the app became available, YES! I thought. Then I tried to collect an outstanding payment on an order and the functionality/button just doesn't exist. So, when will the Android POS app be given the same functionalities as the IOS version? Had Shopify presented a list of features that would be missing from the Android update I certainly would have held off on the investment.
Please explain more about your "outstanding payment" so I can support you better. If you're talking about payments that are not integrated within the POS app, I think ConnectPOS can help you solve this problem. We have the option to create a dummy payment that you can save and follow orders purchasing with outside/not-integrated payment methods. ConnectPOS is also fully compatible with the Android version.