User blog comment:Ieatrice/New Image Galleries Available in Labs/@comment-3247345-20141016025152/@comment-452-20141017235944

3cooldog92, in case you missed it, your question has been answered:

When asked the question "Will this change eventually be mandatory?", BertH has said: We do envision a sitewide rollout at some point after the new editor tool is ready, but there's no date set right now.