Hello Bioh.
If you refer to the OVEnabled key, I believe that is in 7.5 still a valid key.
I only know it from using it to disable OV, but I assume you can use it with a value of 1 to enable OV.
I believe I read somewhere in the 8.0 guides that when the key exists it is not working well together with VaultCache (OV8.0), but I am not sure where I read this.
Do note that building the OV might slow down your network, especially if the EV servers are central, and users access them via slow wa'-lines.
Regards,
Gertjan
Regards. Gertjan