Mobile App Refinement & Publishing

I'm in need of an experienced mobile app developer for the refinement and publishing of my app on both Android and iOS platforms.

This particular project involves:

- Enhancing the current mobile application
- Incorporating new features based on specific requirements

The ideal freelancer for this job should:

- Have prior experience in mobile app development for both Android and iOS
- Be knowledgeable in adding new functionalities to existing apps
- Show adeptness in delivery and publishing of final product in online app stores.

Please provide relevant work samples along with your proposal for my consideration.