If necrozma is indeed in the new Pokemon movie


Games

September 12, 1998 yellow

December 14, 2000 NA July 25th 2001 crystal

September 16, 2004 emerald

September 13, 2008 platinum

June 23, 2012 BW2

November 18, 2016 sun and moon

Movies

July 18, 1998 Pokemon the first movie

July 7, 2001 pokemon 4ever

July 17, 2004 Pokemon destiny deyxos

July 19, 2008 Pokemon girtina and sky warrior

July 14, 2012 kyrmun keldo film

July 16, 2016 volcanism movie with zygard and magerena

The 3rd version of the game had the legendary in the movie the same year.

In zygarde case it was quest and in sun and moon.

So we're either gonna get a necrozma 3rd version or a game with necrozma in it