What is upgrade compliance?

In a typical scenario, vendors use the expiration date to prevent a perpetual usage of the software. However there are cases in which the customer is allowed to perpetually use software Version X, but not Version X+1. In order to address such scenarios, SLASCONE licenses carry an optional maximum software release information, which indicates the latest purchased version. Once an installation is upgraded to a not purchased version, SLASCONE returns a corresponding warning/error.