As we continue to upgrade Rocket League with new technologies, it is no longer viable for us to maintain support for the macOS and Linux (SteamOS) platforms. As a result, the final patch for the macOS and Linux versions of the game will be in March. This update will disable online functionality (such as in-game purchases) for players on macOS and Linux, but offline features including Local Matches, and splitscreen play will still be accessible.
If you purchased Rocket League for Mac or Linux on Steam, the game will still work with full functionality when installed and played on a computer running Windows 7 or newer.
Additional information can be found in the support article here.