mp4 vs m4v: Do I even need an m4v?

Hello everyone, quick question for ya.

I've been creating m4v files for a while now through Quicktime player. Low res video files for older iPhones and iPods. Now I'm using Adobe Media Encoder but they don't encode to m4v, only mp4.

Aside for the DRM and AC3 features of the m4v, is there any difference? Can I safely encode to mp4 without worry?

Thanks