The current Developer-only release is a GM Release Candidate: it may change before release. If you are not a registered developer you should not be installing it.
If you break your phone before 24th and go to Apple store, Apple might refuse service since you have prerelease software installed. Other than that, GM is the final version that is going to be released on 24th.
If you break your phone before 24th and go to Apple store, Apple might refuse service since you have prerelease software installed. Other than that, GM is the final version that is going to be released on 24th.