I hear people on these forums constantly say that Blizzard doesn’t have pre-1.12 data and won’t touch the 1.12 data. However, Blizzard didn’t say this. What they said was:
“This was a good start, but there were issues with how the developers used to handle updates to the database data. Unlike the source code, for which Blizzard had archives for multiple branches of the game that could be worked on and developed as separate pieces, early database data was overwritten with each commensurate update. Thankfully, that problem was fixed very quickly after launch, and when we looked, we found data going back to version 1.12—and even earlier”
So they have pre-1.12 data, but he didn’t say how long after launch the vanilla dev team stopped overwriting data, except that it was very quickly after launch.
Also, during the Blizzcon WoW Classic panel, Ion made a statement on 1.12 data:
“We really had this 1.12 data that we’ve been able to restore and we viewed that as almost sacrosanct. That’s everything from, you know, the world, and the questlines, and the stories, to individual player abilities, creature health, tuning, and so forth. There’s some changes in code and architecture in the way the client responds to the server, and vice versa, that if we let stand using the modern structure, might have caused this data to produce a different result when it comes to things like game balance. And we definitely worried that if we ever felt like the result was different in a way that compelled us to crack this open, it would very much be like opening pandora’s box. Because, the second we start to substitute our modern judgement to solve problems from 12 years ago, we are deviating from our goal of a historical recreation of the game as it was, and making something different, and that’s something we want to avoid.”
“Almost sacrosanct” could mean that Blizzard won’t touch 1.12 data, but it could also mean that Blizzard can change it, but has to be careful while doing so. They’re very wary of changing 1.12 data, that much is sure, but over the entire presentation, every example and statement that touches on changing Classic involves post-vanilla features, and Ion repeats again and again that they do not want to make changes that pull the game away from authentic vanilla. The only exception is class balance, which Ion states will be 1.12 because classes were the most balanced in 1.12. No mention of being unable to revert to pre-1.12 classes, and no mention in the entire panel about being unable or unwilling to revert back to pre-1.12 versions of any aspect of vanilla.
Note the emphasis of avoiding their “modern judgement” and “deviating from our goal of a historical recreation[…]”. This is a theme throughout the presentation.
Progressive itemization is very much up in the air. Besides two words in the classic panel, words that don’t indicate that Blizzard will refuse to revert to pre-1.12 data, I’ve seen no indication and certainly no definitive proof that Blizzard intends to stay on 1.12 data no matter what.