Support for Live photos still is totally missing years after they have been released. It is next to impossible to get Live Photos onto your computer without using icloud photos, which is its own special disaster. Microsoft has announced that OneDrive will bring Live photos this summer and supposidly Google supposidly already supports it (but Google has it's own issues too with local sync). Please don't force us to go to OneDrive...
I think the worst part about this is that we have a file on our phones that is supposidly synced, but Dropbox is actually modifying that file silently and stripping away information as it uploads it, thus giving the impression of copying it, but actually removing parts of it.
I would suggest that you give users the option to split the file into a short video file and a still image file before uploading. This way they can work with the data regardless of what operating system they are using. This would be a real asset to users that are looking for a workflow that supports any sort of image management software and want to keep their Live Photos and don't want to be stuck with iCloud and Apple Photos.