Hello Andreas.

First of all, thank you for reaching out.

The meaning of that log is that we currently expose in OutSystems UI a block that contains a version of the jQuery library and this was a legacy mistake since on a UI framework it doesn't make sense to provide blocks with these kinds of libraries since that should be on the developer's side to use the libraries and the associated versions they want. This being said we'll no longer update this block and we didn't delete it yet to avoid impacts on the current installed base of our customers.
However, we advise you to start using a Script instead of a block and to update to a more recent version that might have several fixes, mainly related to security vulnerabilities. And, in terms of jQuery be careful where and when to use it since our applications are made with React and as you know we can have problems with the different lifecycles of both libs.
Any further questions just let us know.

Cheers,
GM