According to NVIDIA, new 18.104.22.168 PhysX SDK for Linux (both 32- and 64-bit versions) has passed QA process and is available for beta testing.
If you want to participate in beta program, you need to send your request to PhysXDevSupport@nvidia.com
(Provide a description on how are you planning to use the Linux SDK - number of beta testers is limited)
Long awaited event actually, cause after old 2.8.1. SDK many developers have thought that PhysX SDK for Linux was completely abandoned. From now on Linux SDK will be updated accordingly with PC versions.