Running "bundle update" without arguments might break your application

Calling bundle update (without arguments) updates all your gems at once. Given that many gems don't care about stable APIs, this might break your application in a million ways.

To stay sane, update your gems using the applicable way below:

Projects in active development

Update the entire bundle regularily (e.g. once a week). This ensures that your libraries are up-to-date while it's easy to spot major version bumps which may break the app.

Projects that have not been updated in a while

1. Update a single gem conservatively
2. Run tests
3. Deal with the pain
4. Update the next gem

It's also advisable to only update gems for a good reason (security fixes, new features you want), unless you like pain.