ASP.NET Web App Upgrade

I'm looking for an expert in ASP.NET for a comprehensive upgrade of my existing web application.

The project involves:
- Enhancing the User Interface (UI) design to make it more modern and user-friendly
- Improving Backend functionalities for better performance and reliability
- Upgrading Security features to meet the current standards and ensure the safety of our users

Ideal candidates should have:
- Extensive experience in web application development using ASP.NET
- Proven track record of successful UI enhancements
- Strong skills in backend development and security upgrades
- Excellent problem-solving skills and attention to detail