Looks great, I've always found it weird that basic shareable kanban functionality always costs so much.

About the boards expiring in two months: does that mean two months of inactivity?

Boards get removed after 2 months, regardless of activity. This is because of 2 reasons - 1 it automatically removes old/inactive boards from my db :). And 2 it keeps the boards/tasks more focused for about 4 sprints. I've received a lot of feedback about making the boards stay alive as a paid feature, but I'm not going to make something paid when you can just go to a competitor like Trello if you want persistent boards.

Yeah, I like this instantly shareable and trackable in calendar, but I never found anything more convenient than to maintain a kanban board on a excel sheet and the file placed in a shared folder which the team is having most probably to share stuff around.

That's entirely fair! There's also more flexibility in how you run your board with Excel compared to this.