There are differences between free and paid. Vimalin is available for free if needed, but you have access to more features when you buy a license.

You will always be able to make and restore backups with the free version.

You are welcome to use the free version, because if you have a good backup of your important VM’s, then an important part of our mission has already succeeded. It is important for me that VMware users of the desktop products VMware Fusion, VMware Workstation Professional and VMware Workstation Player can make good backups of their VM’s.

Reasons for buying a license 

Of course we prefer that you buy a license. It was quite a bit of work to write this software and by buying a license you help me to be able to support ongoing development. This is the best way to ensure that you will get new features. We understand that you want something extra right now, when paying for a license and not just a promise. This is why there are extra features for our supporters.

Here is the list of the differences between free and paid:

 

Feature Free Paid
Backup VM’s that are shut down Yes Yes
Backup running virtual machines Yes Yes
Add notes to your backup Yes Yes
Compress backup to save space Yes Yes
Decompress backup Yes Yes
Detect existing backups on disk Yes Yes
Manage backups in backup archive Yes Yes
Backup to local disk Yes Yes
Support for multiple hosts No Yes
Backup to network location No Yes
Schedule backup jobs to run at a specific time No Yes
Send an email confirmation about a scheduled backup No Yes
Get our support via email No Yes
Support ongoing development No Yes
     

Note that a paid license never expires.
Each license is tied to the major version of Vimalin. For example, currently the major version of Vimalin is 2, whereas Vimalin 1.x is retired.
As long as we maintain a major version, we will try to keep that version of Vimalin working well on any of the supported platforms.

New major versions will require an upgrade price to stay licensed. (eg. version 3.x will be available for an upgrade price for existing Vimalin 2.x users). All Vimalin 1.x users got a free upgrade to Vimalin 2.x