It’s Catalyst 15.9, which itself is also a beta release. According to AMD, its latest beta driver contains “performance and quality” optimizations for Battlefront, along with the DirectX 12 optimizations for the Fable Legends: Benchmark.
In addition to performance tweaks, Catalyst 15.9 resolves several issues. They include:
-  Diablo 3 crashes in the Act 2 Desolate Sands area of the game
-  The AMD Catalyst Control Center ‘update’ option fails to download the latest driver
-  Dragon Age: Inquisition may crash if launched in Mantle mode
-  The DirectX Diagnostic tool does not report DirectX12 available on supported products
-  World of Warships may crash on some AMD Radeon HD5000 and HD6000 series products
-  Assassin’s Creed®Unity may experience minor frame stutter when AMD CrossFire mode is enabled
-  Anti Aliasing settings not being retained after changes are applied
-  Some Benq 144Hz Freesync monitors may lose the signal while uninstalling the driver
-  DiRT Rally crashes during gameplay and benchmarking when launched in DirectX11 mode on some Benq 144HZ Freesync monitors
There are also a lot of known issues, such as GTA V crashing on some Radeon R9 390X GPUs and flickering in the Battlefront beta if Crossfire is enabled. You can read the full list of issues in the release notes.
As for Battlefront, it releases in beta form on October 8. EA is considering it a “technical test” to give fans a small taste of what to expect. There will be three modes spread across three planets, including Walker Assault on Hoth (40-player battle with Rebels trying to destroy the Empire’s onslaught of AT-ATs), Drop Zone on Sullust (8v8 matches as you fight for control of escape pods), and Survival Mission (play alone or with a friend to hold off waves of Imperial forces).