There are no official dates for releasing the software. But it seems word is going around it could be early next week that some devices will get it. But as no official date has been given, its only a rumour
I saw a post on Sammobile.com saying it could be sometime in April after the S23series gets theirs end of March/early April, that isn't a offical time throu.
It is fascinating to observe the level of interest people have in 6.1. I personally use the S24 Ultra and the Fold 5, and I can assure you that you are not missing out on much with 6.1.