For those who frequently send messages (SMS/MMS) to many people at once, then you should need a group messaging feature, simply because all sent and received messages will be seen in a single thread, so makes it easier to follow conversations between friends on single screen. Group messaging feature is also available to users of the HTC One stock messaging app, but we have to activate it first.
Although this feature has been enabled, some of you might still get an individual reply (not in a single thread), most likely this is a bug in the stock HTC messaging app. You should know, group texting fully supported only on devices running Android 4.2.2 (Jelly Bean), so before we get an OTA update to the latest Android OS, we will experience various bugs when utilizing this feature.
Enabling a group messaging on the HTC One is easy even though the settings to enable this feature is a bit hidden, and several users don’t expect to find there. We need to go to the stock HTC messaging app then go to Settings -> Multimedia messages (MMS) then activate group messaging.
In case you really want to take advantage of the group SMS/MMS on HTC One without seeking a bug just like the stock app, you can consider installing a third party app, we recommend you to use Textra SMS: a simple rich, beautiful and complete SMS and MMS replacement app, messaging group working out of the box with this app.