The NFL has announced that the Jacksonville Jaguars will host the Buffalo Bills, per The Florida Times Union, for their 2015 London "home" game next season on October 25, Week 7 of the season. The Jaguars home slate for the 2015 season looks kind of weak, at least as far as the current state of the teams and their popularity. There were only a few options for who the team could play.
With the current agreement with the International Series, supposedly host teams would not play teams within their own division, so that should have eliminated the possibility of the Houston Texans, Indianapolis Colts and Tennessee Titans as opponents. The Miami Dolphins are on the Jaguars home schedule, but they're also hosting a game in London in 2015 so it was unlikely they would be the Jaguars opponent.
The Atlanta Falcons made the trip this season as a road opponent, so again it made them an unlikely candidate. Then the Jaguars don't know who their AFC West opponent would be yet, though it would likely be the Oakland Raiders who also played in London for the 2014 season.
That left the Panthers and Bills as the most viable candidates and the Bills won out.