MediaItem using XMLRPC

Hi guys.

I’m developing WordPress app using XMLRPC API.
The problem is I can fetch media items data such as image, video, audio, documents via wp.getMediaLibrary API.
I found something that the response of the API is different on each version of WordPress.
So when I tested the API with the WordPress Blog v4.2.11 then I couldn’t see the type(mime-type) info from the mediaItem response.
But when I tested the API with latest version of WordPress Blog v.4.7.1 then I was able to get the type info from the mediaItem response.

What I want to know is exact version that starting to send the type(mime-type) info as as response of wp.getMediaLibrary API. So I can let users know about the minimum required version of WordPress Blog that will allow to use my app without any problem.

Anybody know about it? I think somebody could tell me the code repository where I can look into it version by version or if you are the guy in development WordPress please let me know.

Thanks.

Jusung