Corporate Group Chat App Development

I'm looking for an experienced Android developer to create a feature-rich group chat application with a corporate and professional UI.

Essential features include:
- Message encryption
- File sharing
- Voice and video calls
- City-wise groups
- Location sharing
- 3rd party GPS sharing
- Show business listings

Ideal skills and experience:
- Proficiency in Android app development
- Strong background in implementing secure messaging protocols
- Experience with UI/UX design for professional applications
- Knowledge of integrating GPS and location-based services
- Ability to manage and display dynamic business listings

Please provide examples of similar work done.