I am aware that the Google Earth plugin is being retired and that you are switching to Cesium, but while the Google Earth plugin was working in Firefox a few days ago, it now doesn’t load (I just get the spinning 3D boat).
I don’t get any option to switch to Cecium in Firefox.
If I load the replay in Chrome I get the same spinning boat but I also get the “Try New Version” button.
Clicking the new version loads 20% and then freezes showing the Google Earth background but no boats or controls – refreshing the page will usually get it to load.
I also tried IE which also had problems with the Google Plugin that required an update that wouldn’t install (error 1603) .
The “Try New Version” button was available which worked successfully.
I’m using Firefox 39.0
Google Earth Plugin Version: 18.104.22.1687
Chrome Version 43.0.2357.132
Win 7 Pro SP1
It might be time to switch to Cesium by default.