I'm working on opensource iOS Bitcoin wallet. Anyone can build it and run it (if you care typing a couple of commands on terminal). SegWit-ready; Replace-By-Fee implemented; arbitrary fees. Built with ReactNative & Expo.

Heres the link: https://github.com/Overtorment/BlueWallet Early Alpha, but pretty usable (use it myself in the first place). Still, don't store large amounts. Would really love some contributions on the project. Its ReactNative which means Javascript is used a lot, so if you wanted to jump in Bitcoin development - nows the change. Feedback appreciated!