When I send to my friend messages when he's ONLY on his smartphone,that messages don't have "delivered tag".
If he restart the Smarphone, this problem will be fixed.But this happens again at a random moment.
i will send the email

This has been a problem for a year or two. Sent/Delivered tags work about 50% of the time. They've never addressed it. They need a 3rd tag, viewed, but they've not added that either.
I was able to solve this with someone I was chatting with. We'd been chatting all day and dozens of msgs I'd sent just said "Sent" while I knew they'd been received and replied to. I had them Force Stop Wire and when it was reopened all the statuses changed to "Delivered". Clearly the code exists to do this properly, but it gets hung. Maybe that'll help hunt this down.
Now if we could get a "Seen" or "Read" notification.
Yes, when my friend restart his smartphone all messages changes to "delivered".
The bug persists on 3.14.628,I waited an hour and that was fixed.
No reboot,No force stop.
I concur. 3.14.628. If the messages say "sent" but the recipient has clearly received them, the only two fixes are to either force stop Wire or reboot the phone. Very annoying.
do you have this bug?
https://github.com/wireapp/wire-android/issues/1556
It looks like the problem may be related to IP addressing. If you start a conversation on one network and move to another network with a different IP address this happens immediately. Rebooting or force stopping on the new network solves it until you move again.
I've noticed this between two desktop wire (without smartphones)