Also, for anyone who hasn’t seen, here’s the Blu-ray season 12 packaging for the UK (confirmed not to be region locked, but you do need 50hz compatibility):

Here’s the boring US packaging:

Here’s the complete features list as of now:

Video:
ROBOT

Making Of documentary: Are Friends Electric?
Audio commentary by Tom Baker, Elisabeth Sladen and Terrance Dicks
Robot Rehearsals Read Through (new)
The Tunnel Effect - interview with Bernard Lodge
Behind The Sofa (new)
Blue Peter - 1974
Photo Gallery (updated and HD)
Clean opening and closing titles previously featured on a different release (HD)
Continuity announcements (new)
Production Information Subtitles (new)
Radio Times Listings
BBC Enterprises Literature

THE ARK IN SPACE

Making Of documentary: A New Frontier
Audio commentary by Tom Baker, Elisabeth Sladen and Philip Hinchcliffe
Optional 5.1 surround (new)
Optional CGI effects
70-minute omnibus edition
Roger Murray-Leach Interview
Alternative Title Sequence
Behind the Sofa (new)
Photo Gallery (updated HD)
Continuity announcements
Model Effects Roll
3D Technical Schematics
Production Information Subtitles
Radio Times Listings
Nestle promotional materials

THE SONTARAN EXPERIMENT

Making Of documentary: Like Nothing On Earth (new)
Audio commentary by Elisabeth Sladen, Philip Hinchcliffe and Bob Baker
Built For War
On Target - Ian Marter previously featured on a different release
Location Report
Behind The Sofa (new)
Photo Gallery (updated HD)
Production Information Subtitles
Radio Times Listings

GENESIS OF THE DALEKS

Making Of documentary: Genesis of a Classic
Audio commentary by Tom Baker, Elisabeth Sladen, Peter Miles and David Maloney
Optional 5.1 surround sound (new)
90-minute omnibus edition (new)
The Dalek Tapes
Keith Miller audio from TVC Canteen during Genesis 3 (new)
Blue Peter, 1975
Behind The Sofa (new)
Photo Gallery (updated HD)
Radio Times Billings
Production Information Subtitles (new)
The Doctor Who Annual 1976

REVENGE OF THE CYBERMEN

Making Of documentary: The Tin Man and The Witch (new/updated HD)
Audio commentary by Elisabeth Sladen, Philip Hinchcliffe and David Collings
Optional CGI effects (new)
Location Report at Wookey Hole
Cheques, Lies and Videotape (now HD)
Behind the Sofa (new)
Continuity Compilation
Photo Gallery (updated HD)
Radio Times Billings
Production Information Subtitles

Misc. Extras
Tom Baker - In Conversation (new)
Tom Baker Years Volume 1 (new)
Tom Baker Years Volume 2 (new)
Doctor Who - Times (new)

Disc PDFs:

489 pages of production documentation
1331 pages of script
19 pages of BBC Enterprises sales information for Season 12
47 pages of Radio Times cuttings
45 pages of the Weetabix 1975 promotion
42 pages of the Wall’s Dalek’s Death Ray
12 pages of the Nestle 1975 promotion
59 pages of the 1976 Doctor Who Annual

2044 pages in total.

The following features aren’t included as they’re being moved to the most appropriate season sets:

Doctor Forever - Love and War
Scene Around Six - Tom in Northern Ireland from around 1977/78
TARDIS Cam 1
The Doctor Who Technical Manual PDF
Crosse & Blackwell Promo PDF