Hi.
Technically, your app will be developed for all version of iOS, Android as well as latest SDKs so that it won't have any issues for compatibility. I have developed more than 50 apps during last 5 years of mobile app development and it includes iOS, Android apps.
Currently, nearly 30 apps are on market and you can check them either on real with your device or over the links.
I can start your project immediately, and try to sync timezone with clients so you needn't feel timezone differences as well.
Your app will be the best one once you work with me, and I have confident to provide those kind of apps as I did in the past.
I have all sorts of mobile devices, so that we can conduct test on different environment.
If you are interested about my past works and services, please send me message so that we can discuss further about your project.
Let me know when you have any questions or additional concerns.
All the best