It's not a tear in the space-time continuum. It's not a rogue time traveler, either. If you've been receiving text messages dated 2003 or 2001, you're not alone. Users from all over the world have been reporting the same confusing incident. Blank texts backdated almost 15 years. Some are from mysterious phone numbers and other are from nonsensical sources, like a simple 19 or a crazy-long string of digits. According to The Telegraph, it's no big deal, but it is plenty strange.
Users posted the question to Reddit, where redditors reported these strange texts as far back as 2016. Thanks to some internet sleuthing (and plenty of conspiracies that sounds a lot like Stranger Things fanfic), online message boards figured things out. SMS messages, more commonly known as text messages, go through one of two different transmissions methods. The standard is the text mode that you're used to and the second is PMU, or Protocol Data Unit.
Developer’s Home explains it like this: "The SMS specification has defined two modes in which a GSM/GPRS modem or mobile phone can operate. They are called SMS text mode and SMS PDU mode. The mode that a GSM/GPRS modem or mobile phone is operating in determines the syntax of some SMS [Text Mode] commands and the format of the responses returned after execution."
Sending a message through PDU allows people to change any aspect of the text, from the sender's number to the date sent to the contents of the message. All it takes is some rudimentary hacking know-how and a GSM modem. These mysterious texts are probably just flukes and mistakes from people messing with their own tech.
If you get a message from the past, it's really no big deal. Hacking may sound scary, but we suggest ignoring these clandestine messages. If you're so inclined, you can report the suspicious activity to your carrier. So no, it's not a text from the Upside Down. You can rest easy.