Older devices show overflow icon on some screens but not others
On the Sony Xperia Tipo (Android 4.0.4), which has a hardware menu button, the action bar overflow icon is shown on some screens but not others. For example, it's shown in the private conversation, but not in private groups. This should be consistent across the app.
In screens where it's shown, the menu can be opened by pressing either the overflow icon or the hardware button.