Why is there a charge for upgrades?

Why is it that for the free version upgrades are free but when you buy a Pro license the upgrades are only free for the current version?

Why does EMC add the version to the license? Does not seem fair to charge for upgrades?

This depends on the type of license you have.

A Pro license with Lifetime Upgrades allows you to use all versions of eM Client, with all features enabled.

A standard Pro license for version 8 allows you to use version 8 with all features enabled.
If you want to use it with version 9, you can purchase a version upgrade.

A Free license allows you to use any version for personal use only, with certain features disabled.