My existing iOS e-commerce app is due for a significant refresh and I’m looking for a developer who can step in quickly and guide it from its current stable release to the next level. The core build is written in Swift and maintained in Xcode; everything is already live on the App Store, handling product browsing, cart management, and Stripe-based checkout. Here’s where I need your help: • Modernise the UI so it feels fully at home on the latest iPhone and iPad screens, adopting SF Symbols, dark-mode support, and smooth animations. • Optimise performance and memory usage—startup times and scrolling in the product feed need to be razor-fast. • Integrate Apple Pay alongside the existing Stripe workflow, plus add Sign in with Apple to simplify onboarding. • Ensure every change meets current App Store Review Guidelines, with TestFlight builds supplied for each milestone and unit/UI tests demonstrating stability. • Provide clear, commented code via Git with concise release notes so my internal team can follow along. Acceptance criteria 1. A TestFlight build that passes Apple’s automated checks without warnings. 2. Checkout flow completes successfully with both Stripe and Apple Pay in sandbox. 3. All screens render without layout issues in light and dark mode across iPhone SE through iPad Pro. 4. Unit and UI test suites show ≥90 % pass rate on Xcode’s latest stable version. 5. Clean, documented Pull Request ready to merge into the main branch. If you have a track record of upgrading Swift-based, App Store-approved commerce apps, I’d love to see a couple of examples and hear how quickly you can get started.