How to read the timeline
Each row is one AWS certification and each bar one of its exam versions, from its beta start or release to its last day. A version is announced before its beta, in beta until its release, current once released, retiring once AWS has set its last day and retired after it. Where an old version and its successor overlap, both are on offer and you choose which one to book.
The statuses are worked out from the dates on today's date in UTC. Check the date on AWS Certification's own page before you book an exam.