[Isomorphic]

That's a different widget - you can just repeat the code you already have to set default on DateItem, but for RelativeDateItem instead.

That said, we've just made a minor tweak such that, as of builds dated August 23 and later, you won't need to do this, because RelativeDateItem will pick up it's default from DateItem if one isn't provided.

[anderfim]

We have now reached the end of 2020, and it is not possible to browse past 2020-12-31 for the DatePicker (DateItem). We are using 4.1p nightly build of sept. 8.

[Isomorphic]

Read the posts right above - how to update the range has been repeatedly explained.

Also, your version is past end of life.