There's a long thread in the forum's "Connected Drive/Audio/Video/Electronics..." section, that's been ongoing for a few days about this.
Short summary: with the Lightning adapter, you will not get all of the video capabilities to the screen that you might
have used previously. Otherwise, most will work fine.
We can probably expect a new BMW Media Adapter later; but I've found mine to be mostly useless anyhow, and will make my soon-to-be-old iPhone 4s a permanent 64GB music player that resides in that Media Adapter.
P.S. the iPhone's 30-pin connection is about 9 years old, and was created for the iPod. After about a decade, it makes sense to go from an analog connector to the 8-band digital connector of the new version.
You can find lots of accurate information regarding Apple stuff at:
usually days prior to the regular press reports.