After purchasing a JUCE 5 license I got a serial to redeem a license within the Projucer. The new Projucer splash screen has a “redeem your license here” link at the bottom which opens a new page in my browser where I can enter that serial. But confirming it brings me to the obviously unavailable page
projucer://register-product=‘my serial number’
This page was probably intended to be opened within the Projucer… Hope a fix comes soonish.