I would bet that this is going to be 4.0 quad, like the Blow by Blow, just using the quad master. The people putting the ad together are probably using the term '5.1' as a pseudonym for surround sound. To them anything surround is 5.1
Of course, I could be wrong but I can't imagine them creating a new mix of this album, and I doubt that DTS Entertainments "fake center channel" mix ever left their building. Tad would know for sure
That entire press release struck me as a very rough Google translation into English.
But, it is more confirmation that the labels are seeing those old quad tapes as having value in this modern world. We've been seeing it a bit more in the last two years, but I think even in the last 6 to 8 months we are seeing more and more 70s quad masters being given their fresh new lease on life. I think it's for real now, they know now that it's not insulting to consider (70s Q mixes).
I look forward to the day when AF or AP are scrambling to license quad masters before Sony Japan get first dibs, and that there is a serious competition to get there first. The day when labels don't dare pass up on quad masters, or else face a new release that does feature it, making their expensive undertaking redundant. Maybe Sony Japan will drop us some Santana, or other artists we did not expect due to MFSL getting things tied up.