This is our first stable release! For the time being we have simply copied r70.2 to a new stable release channel, so there are no new changes in r71. For information about recent changes, see the release history.
Now that we have a stable channel, visiting editor.construct.net will load up the latest stable release instead of the latest beta release as it was doing previously. In future to load a beta release you'll need to visit the version directly with a URL like editor.construct.net/r72 (note this URL isn't valid yet). We'll provide a separate notification system to alert you about new beta releases if you're using the beta channel.
From inception to first stable release has been a journey of over three years of continuous development. Check the Scirra blog where we have a special post to mark this milestone!