Disney gets Oswald back! Finally!

[Alex]

Whether they're in the public domain depends on whether their initial copyright registration was renewed in the '60s. If not, then they are in the public domain, if so then they won't enter the public domain until 2022-2023.

Then there is also the trademark issue, if one is on file. Trademarks don't enter the public domain as long as they're maintained so it could be that Disney was also buying Oswald related trademarks from Universal (which would allow them to use the image in marketing and whatnot).