Obviously,the current version 4.21 is not compatible with GVR SDK 1.17. Does anyone have the same problem?
I have scanned through the official website of GoogleVR.However, I cannot open the download web on github they provide.
To see the googlevr github unreal branch you first need to link your Epic account to github as per: Unreal Engine 4 on GitHub - Unreal Engine
Afterwards you can download and compile the engine for the version you are wanting to use (under branches) or just get the googlevr plugin version you are after from:
https://github.com/googlevr-unreal/UnrealEngine