Long-time Star Wars writer Lawrence Kasdan recently spoke to Indiewire and revealed that Han Solo's prequel film will take place roughly 10 years before Star Wars: A New Hope. Here's what Kasdan had to say,
"[The film] will not be, “Here’s where he was born and this is how he was raised.” I think what it will be is what was he like 10 years earlier [than A New Hope]—maybe a little earlier, you’ll get a glimpse. But Kurosawa once said the heroes are the ones that are still changing and the villains are locked and petrified into what they are, and Harrison embodies in Force Awakens someone who is still not settled on who he is."
It is unclear how much information Lucasfilm will grab from The Han Solo Trilogy sci-fi novels which fleshed out the character from his days as a pickpocket street urchin to competitive, racing pilot.
Phil Lord and Christopher Miller (21 and 22 Jump Street) are directing the film which will be released on May 25, 2018 release.