I upgraded to 8.3 last week, and Sunday night all SMS messages (not iMessages) started coming in delayed, duplicate, or not at all. I had to restart my phone about 12 times because it kept crashing, too. Now, I have about 6-8 SMS conversations that I can't delete. I've tried restoring to a backup on iTunes, but it just reloads the conversations with it. Suggestions?
iPhone 5, iOS 8.3
https://www.apple.com/ie/ios/whats-new/messages/
there are two ways to delete messages in ios 8, from the inbox - you can swipe from right-> to left on any message & that will give you an oprion to delete individual messages, theres also edit on the top Left, this allows you to highligh messages you want to delete.
IF you are still experiencing problems id advise you to restore with itunes, this time set the phone as new without a restore of your backup, then when complete setup , test your phone, if it seems ok, you can restore your backup, if its still happening then your backup corrupted
I seem to have the same problem but with an iPhone 6 on Sprint. The iMessages work fine but the SMS messages come in delayed, duplicate, or not at all as your issue. I restored my phone more than once from New and still the same issue. Has been like this for almost a week. I am able to delete the messages but sometimes the messages start a new conversation instead of coming into the same message thread, Nothing seems to work. Have you had any luck?
Deleting SMS messages in 8.3
