I know very little about the issue on iOS since I don't own any modern Apple devices. My
assumption is they (Apple) changed their
Media Source Extensions (MSE) implementation such that it no longer accepts mp4 fragments that do not begin with a keyframe. Such a change would go largely unnoticed because the overwhelming majority of MSE usage is for
VOD where all the video is already prepackaged in chunks that always begin with a keyframe. Low latency live streaming (such as what
Blue Iris's web server does in ALL video streaming cases, even playing recordings) cannot function with such a requirement. The efficiency, the video delay, and the responsiveness would suffer enormously.