A few weeks ago, we reported that some modifications to Cortana were occurring for a select few people running the Windows Phone 8.1 Preview for Developers. By the time we posted an article the changes had rolled back, signaling that Microsoft was testing the waters with the refresh to their new personal assistant.
Since around midnight last night, a few users in our forums are once again seeing the changes, including the screenshots posted below. In addition, a few tips have rolled in from people noticing the new improvements. Unfortunately, only one of the writers on the Windows Phone Central staff have the updates yet, so it's not clear if this is a slow rollout, testing or something else.