They have never expressly changed the view that the ‘creative days’ are 7000 years each. They just don’t mention a specific period anymore. When they do refer to the total length of the ‘creative days’, they say they could have been “many thousands” of years, but never millions or billions. (However, they say that the creation of the universe ‘in the beginning’ up until the initial formation of earth before the ‘creative days’ was "evidently" billions of years, with unconvincing apologetics regarding the contradiction this creates with Genesis 1:16.) Their view remains a form of day-age creationism.
It seems that 1987 was the last time they explicitly said the 'creative days' were each 7000 years. The Watchtower, 1 January 1987, p. 30:
Second, a study of the fulfillment of Bible prophecy and of our location in the stream of time strongly indicate that each of the creative days (Genesis, chapter 1) is 7,000 years long.