The reason these unauthorized keys still activate MathType 6.9 has to do with how the licensing server was configured. Before the 6.x series was shut down, the activation mechanism was relatively simple compared to modern systems. These leaked keys were likely generated using keygens or extracted from legitimate installations, and because the legacy validation server still accepts them, they continue to function.
These are minor version updates. 6.9b and 6.9d include bug fixes and improvements over the base 6.9 release. Product keys may or may not be cross-compatible between these minor versions. product key of mathtype 69
: MathType product keys never use the letter "O" ; any similar-looking character is always a zero (0) . The reason these unauthorized keys still activate MathType 6
To use the full features of MathType 6.9, a is required for activation. Without a valid key, the software operates in a limited "Lite" or "Evaluation" mode. These are minor version updates
Upgrading to the latest official version ensures seamless integration with Microsoft 365, Google Docs, and various Learning Management Systems (LMS) like Canvas and Moodle.