Android Invoicing App Development in Flutter

I'm in need of a skilled Android developer to create a billing app focused primarily on invoicing. The app should be able to generate standard invoices and include the following features:

- Customizable templates: I want the ability to personalize invoices to suit different clients or scenarios.
- Automated reminders: The app should send reminders for upcoming due payments.
- Multi-currency support: Given the nature of my business, the app needs to handle and generate invoices in different currencies.

Ideal candidates will have a strong background in Android app development with a focus on billing or invoicing systems. Previous experience with implementing customizable templates and multi-currency support in apps will be a significant advantage. Please include relevant examples of your work in your proposal.