Wait, multiple messages get concatenated to MMS? In early 2010s I remember in my country it's still concatenated as regular text (so if one part is somehow missing or comes in very late, some phones will only show the surviving parts as one, others dump each parts separately), I guess they remove that functionality? Back then each part cost roughly one cent and plenty of phones in use still don't support MMS, then people just jump into WhatsApp entirely when Nokia support it in their feature phone.