The warning will disappear when we remove the setter and the Obsolete attribute.
Or you can suppress it by writing before using the property:
#pragma warning disable 0618
And if you like you can enable the warning again with:
#pragma warning restore 0618.
In the example above 0618 is the number of the warning. It can be seen in the Output window of Visual Studio.
All the best,
the Telerik team