Yonke imikhiqizo Isithangami Sokwesekwa

I now have two issues, one is that on my IMAP accounts with my own domain, both the recent sent and recent received emails in a thread are showing up twice. This doesn't happen with previous emails in that thread or with gmail, exchange, outlook.com, live.com, icloud, etc.... Now, I have an issue where the pop ups for calendar notifications keep popping up non stop and either won't go away by hitting "Submit to changes anyway" or if they do go away, they immediately pop back up again. 115 is a big disapointment for me, it's been highly glitchy, many add ons no longer, some that should work, don't work properly, it was hyped a major upgrade and I see very little that distinguishes if from 102 in any meaningful way except some of the icons are more colorful. Is there a way to go back to 102? Either that or I may start using Mac Mail again due to all these bugs.