Google AdWords announced they are revamping the URL tracking methodology they used in the past from destination URL to final URL.
With destination URLs, anytime you need to adjust tracking, you have to update the entire destination URL, which would result in a re-review of your entire destination URL causing your ads to stop running during the review. The new final URLs is the upgraded method which does not lead to an ad review, for the most part.
Google says the new upgraded URLs leads to:
- less time spent managing URL tracking updates
- reduced crawl and load times on your website
- new ValueTrack parameters that help you gain additional insights about your ads.
On July 1, 2015 your URLs will begin updating to the new structure, so Google recommends you start testing them out now.
There is detailed help on this change over here.
Forum discussion at Google+ and AdWords Help.