In general an update (bugfixes, indicated by an increased build number) is free of charge (it can be downloaded from the website and used with the existing license key). 

An upgrade offers new functionality (new functionality, leads to a new major/minor version number depending on the level of new functionality). An upgrade requires a new license key. This is offered to existing customers at reduced costs, which depend on the customer's current version. The upgrade costs are based on the cummulative upgrade steps (for example: the costs of upgrading from SAM 5.1 directly to SAM 6.1 are identical to the sum of upgrade steps SAM 5.1=>SAM6.0=>SAM6.1).

When upgrading the license count, or the license level of the same release,  the difference in purchase price is charged.

Please see the detailed price list for the current upgrade prices.