Sample libraries consist of two main components: the samples, and the software engine that controls the samples.
The installer file contains just the software part. When updates, fixes, or new features are added to the software it is only necessary to upgrade the installer file. The new installer will be given a new version number while the samples are left unchanged. You can see which version of the software you are using by going to the About tab of the plugin’s settings screen.
Sometimes changes are made to the samples, such as fixing noise, correcting tuning, or adding additional sample content. When this happens a new set of sample files will be created and these will receive a new version number.
You’ll be notified by email (assuming you haven’t opted out) when an update is issued. You’ll be able to log into your account and download the new files. The update email will let you know if it’s the software, the samples, or both that have been updated. You can also keep track of updates for each product by looking at the Version History tab on the product’s store page.