On Wednesday, October 28 at 10AM (PT) Batman: Arkham Knight will be re-released on the PC. A posting on the Batman Steam Community page gives you the details on what to expect when the re-release rolls around.
At the same time we’ll also be releasing a patch that brings the PC version fully up-to-date with content that has been released for console (with the exception of console exclusives).

This means that next week, all PC players will have access to Photo Mode, Big Head Mode, Batman: Arkham Asylum Batman Skin, and character selection in combat AR challenges. Season Pass holders will have access to all content released since launch, including:

AR Challenges
Crime Fighter Challenge Pack #1
• Financial Crash
• Deconstruction
• Assault on GCPD
• Teen Titan
• Cat’s Conundrum
• Newton’s Cradle

Crime Fighter Challenge Pack #2
• High Interest
• Uncontainable
• Sky High
• Feline Frenzy
• Armored Assault
• Flying Grayson

Crime Fighter Challenge Pack #3
• Chemical Reaction
• Stage Fright
• Cauldron Speedway TT
• Guardians
• Precinct
• Vertigo

Batmobile Race Tracks
• Batman Classic TV Series Batmobile Track #1: Batcave Set
• Batman Classic TV Series Batmobile Track #2: Penguin’s Dockyard
• 1989 Movie Batmobile Track #1: Cobblepot’s Causeway
• 1989 Movie Batmobile Track #2: Joker Parade
• 2008 Tumbler Batmobile Track #1: Ashes
• 2008 Tumbler Batmobile Track #2: Cataclysm

Arkham Episodes Story Packs
• Batgirl: A Matter of Family
• Red Hood Story Pack
• Harley Quinn Story Pack
• GCPD Lockdown starring Nightwing

Skins & Batmobiles
• Batman Flashpoint Skin
• Arkham Origins Batman Skin
• Iconic Gray & Black Batman Skin
• 1990s Catwoman Skin
• 1970s Batman Skin
• One Year Later Robin Skin
• 1989 Movie Batman Skin
• 1st Appearance Batman Skin
• Dark Knight Returns Batman Skin
• Batman Beyond Skin
• Original Arkham Nightwing Skin
• Original Arkham Batman Skin
• Classic TV Series Catwoman Skin
• Classic TV Series Robin Skin
• 1989 Movie Batmobile
• 2008 Tumbler Batmobile
• 1960s TV series Batmobile
• Prototype Batmobile
• 1970s Batmobile Skin