Bumblebee 3.1 Released With Primus Support [Nvidia Optimus GPU Switching]

Bumblebee 3.1 has been released today with support for Primus as an alternative to the VirtualGL optirun backend, along with other enhancements and fixes.
Bumblebee is a (unofficial) tool that brings Nvidia Optimus GPU switching to Linux. Nvidia Optimus is a technology used to increase battery life by switching the dedicated GPU (Nvidia) off when it's not needed; when the dedicated GPU is off, the integrated graphics chip (Intel) is used. Bumblebee also supports legacy Nvidia hybrid graphics.