Since Ask Different was originally conceived, the community consensus has been to not allow questions about Apple’s beta operating systems.
The times, however, they are a changing.
I have just updated the answer that we normally update once Apple finalizes their next OS release and releases it to the general public. Are iOS 9 and OS X El Capitan questions OK? Basically, YES – just because a question is about beta iOS 9 builds or beta OS X builds, it isn’t automatically off-topic.
There are clearly both downsides and upsides to hosting questions about beta software. I fully expect the community to require these questions be of high quality with adequate detail so that users running non beta software won’t be confused by these posts.
The thread used to measure the consensus contains a majority of votes for “yes” make public betas on-topic:
Please comment here or on Ask Different Meta if you have any concerns or compliments about this change. Should the consensus shift, we can revisit this change – in the mean time, fire up some Dylan and let Ask Different help you with answers to your beta Apple questions.