@Barget I’m not the developer of juliaup (@davidanthoff is); however, according to its commit history, the available Julia versions are tied to how recent juliaup is. (Like this one) So it
seems like older juliaup gets older Julia. You can type juliaup list in the terminal to see available Julia versions.
@Shayan I tried juliaup self update myself (on Windows). Still no updates. I have to wait for the newer juliaup available on Windows Store, too.
Edit: According to this post, running juliaup self update is equivalent to going to the Windows Store and clicking the update button.