iOS 13 was released to the public for all compatible devices on the the 19 September 2019. On the 24 September 2019, iOS 13.1 released as an upgrade.
iOS 13 New Features
iOS 13 adds new ways to protect privacy, slight improvements that make your iPhone even faster. Adds a dark mode to all system apps accessible from both settings and the control centre. Adds portrait lighting control which allows the user to change the intensity of the lighting in portrait mode. High-Key mono, adds a monochromatic effect to portrait mode photos. Changes to the photo app, all-new curated photo tab. Adds a Years, Months, Days and All Photos slider and tabs to the app. Redesigned editing inside the Camera app for both photos and video. Adds a sign in with Apple. Adds HomeKit secure video which introduces camera storage that is secure and private (hopefully). The Maps app has been redesigned to have a Look Around mode, think google street view but a better version because it's from Apple. Adds Detailed map features and a redesigned Favourites tab. Siri is updated to be more efficient and faster. Adds a built-in app, Shortcuts that works with Siri. Personalised HomePod allows Siri to recognise all members of the family. Siri can now announce messages with AirPods. Audio sharing with two sets of AirPods or PowerBeat Pros. Adds New Memoji's. Adds Memoji to devices that didn't have access to them before. Adds Memoji stickers. QuickPath typing. All new reminders app. Adds Quick Toolbar and Smart Lists. Redesigned CarPlay Dashboard which makes the view more simplified. Less cluttered. Adds the Calendar and Music app to CarPlay. 30% faster FaceID (still not as fast as TouchID). Twice as fast app launch speeds and smaller download sizes for most apps. ARKit 3 allows for virtual objects to be naturally placed in front of or behind people. Adds Apple Arcade which allows you to play over 100 apps designed just for Apple. Voice Control. New text formatting in the mail. Improved Notes app. Added gallery view, quicker search tool, checklist options, shared folders. Redesigned Health app. Easy to access information. Menstrual cycle tracking. Improved startup page in Safari, adds Siri suggestions, favourites and frequently visited websites. Updated Files app allows access to external drives and other cloud drives such as DropBox and Google Drive. New Share sheet.
iOS 13 Compatibility
iPhone 11, iPhone 11 Pro, iPhone 11 Pro Max, iPhone Xs, iPhone Xs Max, iPhone XR, iPhone X, iPhone 8, iPhone 8 Plus, iPhone 7, iPhone 7 Plus, iPhone 6s, iPhone 6s Plus, iPhone SE, iPod touch (7th gen.)
iOS 13 Developer
Developing for iOS 13 is better as is easier to take advantage of the improvements made to Siri, Shortcuts, Camera API's, ARKit 3, Reality COmposer and RealityKit. Mostly developing apps with dark mode and apps with AR.