Sandstorm itself is updated at least once a month:

https://github.com/sandstorm-io/sandstorm/blob/master/CHANGE...

A few of the apps get regular updates, but admittedly a lot of them have gone stale. Sandstorm's security model makes it so that this isn't a security risk in the way it would be on other platforms, but it's certainly disappointing if you're looking for the latest versions of apps.

It's no longer supported by a company so its pace of development has slowed, but it's still an active project, albeit one run by a small number of volunteers. I'm sure they would appreciate any contributions.