To build app, please download latest source code version at https://clients.moosocial.com/, unzip, read the readme file inside to know how to configure to build apk and ipa. For coding environment follow below recommendations:
Android: Android Studio 4.0.2, https://developer.android.com/studio/archive
IOS: xcode 10 +
Post a ticket here if you have any issue when working on the source code.