Sabine N. @Pedro,
that's not completely true, updates, as you say, are not restricted to 6 months, but upgrades - thats a big difference! Actually thats usual and a lot of programs do not even give 6 months free for upgrades to new versions, but usually you just get a lower price if you wish to upgrade. Here its 50% off for existing users. So, if they even give 6 months free, that is actually positive, the more as the price for SoftCat isn't really much.
Quote from their FAQ:
Update - is a program release featuring minor software improvements. Updates for the current software version (for example an update from version 3.01 to 3.10) are provided for any registered customers free of charge.
Upgrade - is a major program release (new version) featuring major software improvements and new functionality. Upgrades are provided for any registered customers free of charge within 6 months after product purchase.