Here's my situation. I subscibed for a year for the supporter "level". If after this year Roll20 is still here seemes to be here for at least another year and I want to use it I'll be upgrading my level to mentor (assuming the levels don't change). Because I can't find any information about the subject I'm assuming the following:
If you upgrade to mentor level it starts immediately and the remaining supporter level subscription is lost.
There is no way to choose to change the level of subscription in advance. I mean that now my subscription will be automatically renewed as supporter level and there is nothing I can do to change this.
The best course of action for me is to cancel my subscription and wait until my level drops from supporter to free and then subscribe for mentor level (if I still want to use Roll20).
Any comments from people who actually know how this works? Edit. And before anyone asks what's the problem the problem is that I'm fairly sure I can't remember to subscribe for mentor level the day my supporter level will be renewed.