One Time Dialog

Just wondering if anyone has any ideas on a one-time dialog I’d like to display for one of my addons.

I’m looking to adjust the functionality of a particular addon that impact users. Specifically I’m combining some of the addon settings into a new way of setting it up. The result is that if they had settings on the old system they’ll have to re-add them to the new one. When the addon updates I’d like to display a one-time notification when the service starts along the lines of “this addon has changed, check your settings or it won’t work” so that people don’t just assume it will be fine but it isn’t.

Is there a good way to do some kind of one time notification? Easiest way I could think of was to display it and then write a boolean value to a file or something to make sure it doesn’t pop-up again. I could then remove the code in any future release since it won’t be needed. Is there a better way? Or should I just assume users will figure it out?

Thanks for any ideas.