The creation days have been of undefined length in JW mythology at least as far as I can remember.
Your memory doesn't go back too far... Fortunately mine does. Each creative day is 7,000 years in length.
One reference: From Paradise Lost to Paradise Regained (1958). Page 10.
Each creative day being only 7000 years long....Not to be confused with how old the Universe is
Genesis 1:1 The creation of the Universe. Millions of years ago....
Yes, that is the WT doctrine. Universe and planet Earth created millions of years ago. The 7,000 year creative periods started not too long ago (in a cosmic sense). Man created 6,000 (a little over now) years ago.
These days they never mention the 7,000 creative day. They just say 'thousands of years' or 'long periods of time'. But - they have never retracted their previous statements. They have never refined those lengths of times. They have only blurred the lines in order to keep dubs ignorant.
Their only scriptural defense for saying universe/earth created millions of years ago is Genesis 1:1 as already stated. However, that is vague, and purposely so on the WTS' part. Because in Exodus 20:11 it says, "For in six days the Lord made the heavens and the earth, all that is in them..." shooting down in one half verse the entire WT creation doctrine.