This is a workaround for adding assets that have not yet been updated to the latest engine build. In 99% of cases you should be able to use them regardless.
Add to Project
If you know the asset worked before and consists mostly of meshes or sound files, you can simply add it like before, but because the new engine version isn’t present, you need to click on Show All Projects, select your project, then at the bottom select the last known version that works.
If the asset in question is a Create project and not Add To Project, you can create it for an older version and then switch engine version and select a new one.