There is a library update in the community commons wich the rest modules makes use of. (string utils) because of this when importing both modules into a project it will result into compile errors. the rest module needs to be update ^^
Robert, check out this issue on GitHub. Michel and Mark both say it's working with after some troubleshooting.
Just released version 1.5.0 of the rest module, which runs on Mendix 5.16.1, community commons 5.4 and added support for decimals. Should be available in the appstore soon.