We've recently introduced a feature on version 3.4.1 of the Android app that allows you to migrate your projects from the old version (2.7.3) of the app. You can head over to the Google Play Store to get the new app.
The migration tool allows you to move over your projects from either the local device (if you are using the same phone with the new version) or through your Google Drive backup.
1. Tap the Settings icon
2. Choose "Migration from old app."
3. Choose between "Local Folder" or "Google Drive"
4. If you've chosen "Google Drive," sign in with your Google account (make sure that you use the same Google account that you've connected with the old app)
5. Select all the projects you want to migrate by tapping the checkbox
6. Tap on "Import Projects" and wait for it to complete
Once done, all the imported projects are available for you to access, edit, and mash. Click here to learn how to edit and manage projects on 1SE.
NOTE: Merging timelines from the old app and the new one isn't possible. The migration creates new projects in the new app.
If you want to make a video that contains the content of two projects, you can mash them separately and later stitch them together with a video editing tool such as Adobe Premiere Rush.