Update 10 Simple iOS and (maybe) Android Apps

I have a collection of 10 mobile applications that need to be updated. They were originally developed for iOS and Android. The primary goal of this project is to bring them up to the latest standards, as they are now outdated.

Key Requirements:
- Update the existing features: The functionality of the apps should remain the same. You will need to ensure that all the existing features are optimized and fully operational.
- Optimize performance: We are looking to improve the performance of these apps. This involves refining the code, eliminating any bugs, and ensuring the apps run smoothly and efficiently.

Optional Requirement:
- Design Update: While not a top priority, we may consider updating the design/interface of the apps. If you have expertise in app design, your input would be appreciated.

Ideal Skills and Experience:
- Proficiency in iOS and Android development
- Experience with app optimization
- UI/UX design skills (optional)
- Familiarity with updating legacy applications
- Strong communication skills; you may need to explain changes to me

Please note that placeholder bids will not be considered. I am looking for a professional who can take this project seriously. Thank you for your interest.