Question I have purchased a Multichannel Mastering license for my (black) Reverb 6000 and activated it. The stereo algorithm should be included, but on the license page it is shown as "inactive". Is the algorithm available or not

This is a graphical mistake on the original Reverb 6000. If you activate the Multichannel Mastering license, the stereo algorithm is also active even though it is shown as inactive in the license page. It is the same for Toolbox 5.1 which is also included with the license but shown as inactive. If you go into the library, you will see that it is possible to load the presets. On the Reverb 6000 MKII, this error has been fixed, and  the Stereo Mastering and Toolbox 5.1 licenses will appear as "bundled" if the Multichannel Mastering license is activated.