Firefox 38.4 addon with mp4 video

Hi ,
Is there add-on which can be used in firefox 38.4 version for mp4 video play? Thanks

Do you really mean 38.4 - a 5 year old version?

Some program need the version use

38.4 was released in 11/2015

This question from 2015 suggests that it should support mp4. Maybe you need some codecs - depending on your operating system.