Instead of dropbox, I'd recommend using something decentralized like Syncthing. I have a similar setup and recently changed to using Syncthing to keep my password database synced on all my devices.

Thanks! Actually never heard about Syncthing, looks really good!

And for android : Keepass2Android is very good

Glad it's working for you as a trust no one solution. But does it concern you that you're telling the world your op sec?