In whatsapp, when you open a group chat for example, you see just above the new messages that were posted a little banner "New messages /unread messages". I find this feature really helpful to not be lost in a conversation.
I agree, it is especially useful in group conversations.
Here's a screenshot in Whatsapp:

Yeah, i like this idea. Thanks for submitting the issue!
+1
Any news on this feature @mcginty ?
@jocelynthode been taking care of more pressing functional issues. These aesthetic changes are still certainly considered, just triaged at a lower priority an we have limited resources.
@mcginty : No worries ! Take your time for the more important issues. I certainly understand that minor things like these are less important than others.
This is my second complete rewrite of this comment... I see code that seems to refer to the read state of messages, but I might be mixing it up with the read state of threads that's used to embolden the text currently.
I dumped the sms and mms DB schema on the wiki for reference in the future. It appears that the mms table has a columns named read and read_status. I need to determine how they're used before duplicating it in the sms table and plumbing it through the various MessageRecord classes.
Fixed by d9b42c4
Most helpful comment
Fixed by d9b42c4