Messages constantly shows un

Do you mean it shows a red badge on the Messages app?

If so, check the Voicemail tab and delete any Voicemails you have there.

DianeKE (Author)

Another item or condition which may (or not) appear,

is that sometimes if your iPhone is not using Cellular

Data, it may not reveal some missed voicemail calls

or images may not show up. A newer iOS can show

odd effects, if signal is poor, &/or settings wrong.

Other user's experience can be matter of settings.

Mostly happens with non-Apple device/user; or if their

iPhone is not actively using iMessage; & Android user's

images won't appear, with their text SMS messages.

IF this happens, or contributes to odd issues, that might

be due to the cellular provider, or use of a Low Data Plan.

Calls from my sister in NM, & their Android phones tend to

show missing images; & much extra troubleshooting, on my

end in AK, means little, to what their household is aware of..

As fans of non-apple products, her husband 'sees' nothing.

.Not that something there isn't amiss. ~ Avoidance is a cure!

..In any event, take care..