A few people have mentioned that The White Album was the point that The Beatles moved from 4-track recording to 8-track recording. While this is true it's worth remembering that the transition happened
during the recording sessions, not at the beginning. A good many of the tracks were done on 4-track, with bounce downs as per the method used on Pepper. I suspect that the 5.1 remix will have the benefit of access to the pre-bounce down tracks as before.
Out of interest I've put together this list showing (for each track) whether it's 4 or 8 track and the number of tape generations used. Info was gleaned from Lewisohn's "The Complete Beatles Recording Sessions" and
www.thewhitealbumproject.com
Back in the USSR - 4-track 2d Generation
Dear Prudence - 8-track
Glass Onion - 8-track
Ob-La-Di, Ob-La-Da - 4-track 3d Generation
Wild Honey Pie - 4-track
The Continuing Story of Bungalow Bill - 8-track
While My Guitar Gently Weeps - 8-track
Happiness is a Warm Gun - 8-track 2d Generation
Martha My Dear - 4-track 2d Generation
I’m So Tired - 8-track
Blackbird - 4-track
Piggies - 8-track 2d Generation
Rocky Raccoon - 4-track 2d Generation
Don’t Pass Me By - 4-track 3d Generation
Why Don’t We Do It in the Road? - 4-track 2d Generation
I Will - 8-track 2d Generation
Julia - 4-track
Birthday - 8-track 2d Generation
Yer Blues - 4-track 2d Generation
Mother Nature’s Son - 4-track 2d Generation
Everybody’s Got Something to Hide Except for Me and My Monkey - 4-track 4th Generation
Sexy Sadie - 4-track 4th Generation
Helter Skelter - 8-track
Long Long Long - 8-track
Revolution 1 - 4-track 4th Generation
Honey Pie - 8-track
Savoy Truffle - 8-track
Cry Baby Cry - 4-track 2d Generation
Can You Take Me Back - 4-track
Revolution 9 - 4-track
Good Night - 4-track