Yes, after the trial period runs out, the program changes into the free version until you install a license. This also means that there is a commercial variant of the program that has a few more features.
If all features are free then eventually development would cease on it. Not because of desire, but because that is what has been learned from working a lot on open source software before. Free software is great, but in order to be able to dedicate time to improve it, money helps.
You can however still use Vimalin without paying for it as we believe that everybody should be able to create good backups.
Running a backup on demand and deleting/restoring your backups is part of the free features.
Scheduling backups so that they run automatically, get email notifications of the result and being able to contact support are all part of what you get when you buy a license.
But we suggest to try before you buy. You can test the full package for 60 days, just download and install. After 60 days Vimalin will revert to the free license and you can continue to use it as long as you want.