Thanks for creating the issue.
I have to look again. I had come across Calendar Systems earlier. I don't really remember the reason I couldn't use it then and that is why I wrote this. Of course, things might have changed now.
I had seen another solution (it might have been calendar systems or something else) which only supported changing the dates throughout the site. I didn't want that.
I will try to review calendar systems again in the coming week and see if there is a difference in use cases. It will be great if you can help. This module just provides field widget and formatter and does not do anything site-wide.
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