I haven't kept us with the latest cases, but I'm not sure where it falls on app-based SaaS. I.e. If I use an app, on a system in which app updates are possible

I haven't kept us with the latest cases, but I'm not sure where it falls on app-based SaaS. I.e. If I use an app, on a system in which app updates are possible, which encrypts my data locally and stores it on their cloud, then the owner/responsible party for the app is...?