Where are the playback states saved?

Hello,

I want to synchronize my playback states with symlink and Dropbox.
Can someone tell me if it’s possible, and if yes, in which file the playback states (which episode have i already watched, …) is saved?
If not, is there a other possibility, except Emby?

Thanks guys

EDIT: I use 2x Windows and Krypton 17.1 if this info is necessary.