# Upgrade to v2.0

pkpy v2.0 is a C11 project instead of C++17. All your existing code for v1.x won't work anymore.

We provide two API sets for v2.0, C-API and pybind11 API (C++17). If you are a C user, use the C-API. If you are a C++ user, use the pybind11 API.