While we develop Marvin, we often release new versions to our pre-release channel. You can access it by adding "pre" to Marvin's URL: https://app.amazingmarvin.com/pre
We often point users there when we fix bugs or add small new features so that they can be tested and/or used right away.
Each time you load pre, you'll see a brief warning message indicating that you should make regular backups. This is shown to indicate that pre tends to be a bit less stable than normal. Probably you won't lose any data, but making backups is a good idea in any case! If you use the desktop application, then automatic backups are enabled by default.
There isn't currently a pre-release channel for our desktop apps, but this is planned.
Thanks for helping us test! If you find a bug (in the app, or on pre), please use ? → Contact Support (or just email us).