There is yet only a draft of those, in version 4. I believe they will be publicly available only after release, but over at
Mulsanne's Corner you can read about them.
Nevertheless, there will be few changes in chassis regulations, except for the mandatory rear fins. The new engine capacities are known for a long time, this new version brings some definition to hybrid rules and allowed "electrical" capacity and the current cars will be eligible to run under further restrictions, to make them slightly less competitive than 2011 regulations-engined cars.
