Finalize iOS App Development

I need an experienced iOS developer to finalize my app, which is 90% complete.

Key tasks include:
- Optimizing performance, especially for system version support

The app should be compatible with iOS 14 and above.

Ideal skills and experience:
- Proficiency in Swift and Objective-C
- Experience with Xcode and iOS debugging tools
- Strong knowledge of iOS performance optimization techniques
- Familiarity with app compatibility across multiple iOS versions
- Attention to detail and a commitment to delivering high-quality work

Please provide a portfolio of similar projects and an estimated timeline for completion.