Back in November last year, Google rolled out a new-look Google+ and deemed it a 'preview' of what was to come. It was generally assumed that at some point this would replace what has become known as 'Google+ Classic,' and that day has now arrived, with the announcement that the Web preview will be the default look from today onwards.
This isn't entirely a surprise: last week Google issued a reminder saying that today was the day, so we were prepared for this eventuality. That said, I personally find the Web preview better than the Classic interface - I much prefer the material look over the somewhat out-of-place design and general jankiness of Google+ Classic. Some will undoubtedly disagree with this though, but for those people it doesn't get any better: the option to switch back to Classic will disappear in the next few weeks as Google+ becomes a 'core Google Apps product.'
Along with this news, Google is adding some new features to Google+. You can now embed links and photos in comments, and Communities will get approved posting, so moderators can approve who posts what. There is also a new notification centre coming, and Google+ will become a Google for Work product for Google Apps users. All these changes will roll out to the Android, iOS, and web Google+ apps "in the coming weeks," which we assume means server-side switches and rollouts.