Spot on Oubliette!
I said this in another forum:
Annual meeting 2012 if I recall was the first mention. The first published change appeared in THE WATCHTOWER (STUDY EDITION) JULY 2013, 2nd article
From paragraph 17
All faithful anointed ones who are still on earth after the initial part of the great tribulation has passed will already have received their final sealing. Then, as indicated in Jesus’ prophecy about the great tribulation, they will be gathered to heaven.
See the timeline picture too.
This new article addresses the "rapture" label now that they teach rapture (for the remaining anointed).