I recall there was an issue with email messages whenever a member changed their plan in an 'exclusive plans' setup.
For example if they changed from Plan A to Plan B using the 'upgrade' feature with the setting as "same duration' they were still receiving renewal/expiry notices on the old Plan A even though they had renewed their current plan.
If they process upgrade upgrade their membership, I don't see how this issue could happen (at least by checking the code in latest version). So I believe this issue was already hosted
