Mini from the Google AdWords team announced on Google AdWords Help that they've "made some changes to the Google AdWords exams and certifications in Partners."
One change not specifically announced or mentioned by Google is that they cut down the certification period from 24 months (two years) to 12 months (one year). Rodney Hoover spotted this and posted it on Twitter. Again, you become certified today, that certification is only valid for a year, not two years anymore.
You can read it on the updated help documents:
A passing score on an exam is valid for 12 months after the exam date. To maintain your AdWords certification, you'll need to have valid passing scores on at least (1) the AdWords Fundamentals exam and (2) one of the other advertising exams (for a total of at least 2 passing exam scores at any given time).
The older version doesn't really mention it.
Mini from Google added:
- To earn the AdWords certification, you need to pass the AdWords Fundamentals exam plus any one of the other AdWords exams (Search, Display, Video, or Shopping).
- We’ve also released a new version of the AdWords *Fundamentals* exam that includes the latest changes to AdWords and has a greater focus on best practices.
Forum discussion at Google AdWords Help, Google+ and Twitter.