We typically develop against the latest stable version of Xcode.
As of this writing, that's Xcode 12.4
Clone the repo to a working directory:
git clone https://github.com/oxen-io/session-ios.git
We recommend you fork the repo on GitHub, then clone your fork:
git clone https://github.com/<USERNAME>/session-ios.git
You can then add the Session repo to sync with upstream changes:
git remote add upstream https://github.com/oxen-io/session-ios
To build and configure the libraries Session uses, just run:
Session.xcworkspace in Xcode.
In the TARGETS area of the General tab, change the Team dropdown to your own. You will need to do that for all the listed targets, e.g. Session, SessionShareExtension, and SessionNotificationServiceExtension. You will need an Apple Developer account for this.
On the Capabilities tab, turn off Push Notifications and Data Protection, while keeping Background Modes on. The App Groups capability will need to remain on in order to access the shared data storage.
Build and Run and you are ready to go!
Features related to push notifications are known to be not working for third-party contributors since Apple's Push Notification service pushes will only work with the Session production code signing certificate.