[add more info for Johan here]
The official Wikipedia iOS app has released a new version (6.2) to the App Store. This version makes major improvements to the wikitext editing tools, including syntax highlighting, night mode support, find-in-page and mobile toolbars for common syntax. We're already starting on a follow-up update, so if you edit and use iOS, we look forward to hearing your suggestions for how to make it even better.
Link to app store: https://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=324715238&mt=8
Link to project page: https://www.mediawiki.org/wiki/Wikimedia_Apps/Team/iOS/Editing_program