As of Wednesday, McDonald's has not said anything about exactly when, where, and how you can get your hands on some Szechuan sauce. The company appears to be saving those details for its announcement on Thursday.
In case you were off-planet somewhere last year, the company's limited-release-gone-wrong happened on October 7, and the response bordered on apocalyptic. Put simply, there wasn't enough sauce and people lost their damn minds. Those folks who couldn't find their minds were mostly fans of the animated series Rick and Morty, the Season 3 premiere of which featured Rick shouting about how his life's sole mission was to have McDonald's Szechuan sauce again.
The sauce/suspected ichor was originally released to promote the Disney movie Mulan back in 1998. To be clear: It was all a bit that a bunch of people took way, way too far. McDonald's was trying to play into the joke and angered the fans, and now must pay the blood sacrifice: bring back the sauce again.