To develop for Oculus 1.3 you'll NEED to specifically be using Unity 5.3.4p1:
(If you are using the 32-bit version of Unity, you will need to use the 64-bit installer to install just the build engine for PC/Mac/Linux)
You will also NEED to download the OVRPlugin separately and patch Unity:
The OVRPlugin just mentioned has very special and particular instructions:
After you have downloaded and installed Unity 5.3.4p1, take these steps to install OVRPlugin:
- Close the Unity Editor if it is currently running.
- Navigate to the following directory: C:\Program Files\Unity\Editor\Data\VR\oculus.
- Delete all contents of the directory.
- Extract the OVRPlugin zip and copy all files into the directory C:\Program Files\Unity\Editor\Data\VR\oculus.
Note: Do not install OVRPlugin version 1.3.0 with any version of Unity other than 5.3.4p1, or it will not work properly.
Finally, you'll have to update the Oculus Unity Utilities: