Unfortunately not, it is not possible to get the updates in a used app automatically.
However users figured it out in a couple of steps to be done, so you could apply the updates to an existing app.
Here’s the guide:
- create a test app with the updated ‘theme’
- export that as test.bubble (Settings > General > Scroll to the bottom > Export Application)
- then import that into the current development area (Settings > General > Scroll to the bottom > Import Application - into the one I want to update)
- it updated it with the changes done by the publisher
- the only issue(s) will be design changes that you made previously, they will be lost.
This way all the data will be kept.
The other way is to create a new app from the updated template and work from there.