I have the latest Windows client (8.3.2) working in Wine staging 6.19. I was not able to get it working with other versions of Wine and it only works with the staging build. 6.19 is the latest release so hopefully that means it will continue to work going forward. Almost everything is working. I can configure my NVR and cameras, view the cameras, and watch playback. The only thing that doesn't work is the mute button and volume slider. If I have a camera selected that has audio enabled I hear the audio at full volume no matter what the volume slider setting is. Otherwise there's no issues. Installing the staging build of wine will depend on which Linux distribution you are using.

I'm not sure why it is so difficult for them to release a native Linux client. The client is Electron based. At least it's working and I don't have to use the browser which can't display the cameras in clear mode.