On Release Note of Google VR SDK for Unity v1.40 (April 2017) https://developers.google.com/vr/unity/release-notes
Note: You must enable dynamic library loading in VrCore to get the latest C++ GVR Updates. To do this, go to Settings > Developer Options
Enable Library Loading. If Developer Options are not visible, tap 7 times on Build Version.
I'm looking for on Nexus 5X(7.0), Nexus 6P(O Preview), Pixel XL(7.1), I cannot find "Enable Library Loading" setting in Developer Options. What's mean this?
This option is only available from the VR developer options.
To access the option :
Go into the settings menu, either via a regular menu (in the Daydream app for example), or by pressing the small gear in the top right corner if you are in stereo mode
You should see a settings menu with "Build Version" at the bottom of the list : tap on it several time to activate the developer mode