Marvel franchise to go for a complete name change for the previously titled movie series - Avengers Infinity War I and II. According to the source, the two movies will divert from the original story significantly.
The two stories under the name Avengers Infinity War is all set to be two diffetrent stories altogether, and thus grouping them under the same brand would be misleading to the fans and the viewers, feels the Marvel franchise.
It is speculated, that the certain diversion in the stories which were earlier not planned, is all for the sake of accommodating new characters and developing potential conflicts, which actually can be viewed as a good thing for the fans.
However, the one thing that will remain unchanged is the release date of the movies. The first installment of the Infinity War, is all set to release on May 4, 2018 and the other untitled part will be released on May 3, 2019.
There have been many speculations, regarding the title of the movie, but the producers remained tightlipped about this. They would certainly look to modify a great portion in the story and the title will only be revealed after that, mainly because of the rumoured death of Hulk in the second part.