Hello Luc Baeten,
You could download the trials of any version of the RadControls for ASP.NET. Once they are put in the project's bin directory, they could be used with no limitations in that project
. This means that they will work as standard developer license.
Furthermore, you can find information on how to migrate the RadControls in Sitefinity project in the KB Article How to upgrade RadControls
I hope this helps.
the Telerik team
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