If you want to work on your app without affecting the published version your users are interacting with, you can pin the published version to a particular version.
Click on ‘View history’ in the App Browser to get a tree of versions of your app. Each version has a ‘Publish’ link - click this and a ‘PUBLISHED’ icon appears next to that version. Now, users accessing your app will see this version. You can make changes without them affecting what the user sees.
When you hit ‘Run’ in the Editor, you’ll still see the development version. This allows you to test your development version. The published version will not be affected by this.
When using the Uplink, you have access to two keys: one for the published version, and one for the development version. This allows you to have published and development versions of the code you’ve connected to the Uplink as well. Note: the development version of your app will fall back to the published Uplink code if the development version is not available.
To programmatically check whether the published version or development version is running, use
if app.branch != 'published': print("Dev version of the app has been accessed")
See Version Control for more information about version control.