Solo obviously takes place before A New Hope. However, we weren't sure where exactly it takes place in the official Star Wars timeline. Now, we know where it fits into the grand scheme of things and it will not end as close as Rogue One did to the original trilogy nor will it butt directly against the beginning of the aforementioned prequel. The timeline has become an important piece of information for Star Wars fans, especially since all of the new trilogies have been announced.
It had been previously reported that a bunch of tie-in Solo books are being released ahead of the movie. Some of which tell the story before the events of the upcoming big screen adventure, while others like The Last Shot, jump around from before, during, and even as far as after the events of Return of the Jedi. It's been announced that all of the recently unveiled books will be a part of the official Star Wars canon, therefore making them a part of the official timeline as well.
The publisher, Del Ray, has put out a number of official Star Wars books over the years and they are responsible for the new Solo: A Star Wars Story books as well. The Del Ray website was recently updated to place the new books into the Star Wars timeline and both The Last Shot and Solo books take place after James Luceno's Tarkin novel, which is set 14 years before A New Hope. This falls in line with what had been previously reported and means that the movie will take place well in advance of Rogue One and A New Hope.
Disney CEO Bob Eiger had previously revealed that Solo would span the course of 6 years of young Han Solo's life, from the ages of 18 to 24. Since Han is around 29-years old at the time of A New Hope, that would mean that the upcoming movie starts about 11 years ahead of the original trilogy and ends 5 years before the events in Rogue One. So, we will not see anything like we did when the last spin-off hit the big screen in terms of how closely it tied into A New Hope. This also means that the movie takes place before the Rebel Alliance was any type threat to the then hugely powerful Galactic Empire.
With the open timeline in between the events of Solo: A Star Wars Story and A New Hope, the door is open for Disney and Lucasfilm to tell more stories that take place in between both movies. It will be interesting to see where the Obi-Wan movie fits into the official Star Wars timeline as well as where Rian Johnson and David Benioff and D.B. Weiss decide to go with their new movies that will take place outside of the Skywalker saga. You can check out where Solo: A Star Wars Story fits into the official Star Wars timeline over at Randomhouse.