As of v2.0.0 for the Dropdown components, the valueField prop was removed. An example of how to re-implement the feature is provided here:
https://www.telerik.com/kendo-react-ui/components/dropdowns/combobox/common-scenarios/#toc-using-data-fields-for-values
The thing for me was that I am using TypeScript and needed a type safe withValueField HoC so I copied the existing HoC and added some type safety. I figured it would be helpful for any of those that are looking for the same thing.
Check it out here: https://gist.github.com/Weffe/c69304a00e5f955a13cae65bbcb0a86d
Enjoy!