All moved to W10 and very few problems. Your choice to stat with Dashlane but get to their support since I found no indication W7 or your iPhone 5s (Hey, I have that phone) would be a problem.
I've heard a lot of W7 bugs too so we can dig up dirt on any OS. My bet is the issue is something Dashlane knows about. Ask them.
Dashlane Premium no longer works on my I phone 5 S with Windows 7
it wants me to install Windows 10. I am happy with windows 7 but a lot of new apps require Windows 10 I have heard lots of bad news about W 10 bugs and my son says I should'nt go there yet. Any suggestions will be appreciated.