With the release of "Red Dead Redemption 2" confirmed for fall 2017, Rockstar Games already has one hit title sequel coming out this year. Ergo, it makes sense that "Grand Theft Auto 6" will be pushed back to 2018 as the earliest.

Some fans are now turning to previous GTA releases for clues, pointing out the four-to-five-year pattern between the first couple titles. Others posit that a 2020 release is more plausible, giving Rockstar a three-year breather between RDR2. One recent speculation comes in the form of a supposed Easter egg spotted in GTA 5 by a YouTube user.

'Grand Theft Auto 6' Coming 2021?

This theory is suggested by YouTube user Itz Frolickz, and it's based on some seemingly random door numbers in the airport in "Grand Theft Auto 5." You can check out the video below to hear the full explanation, but it's basically as simple as that. If you go to the airport in GTA 5 and drive around the smaller corridors, you can see two doors side by side with the numbers 2013 and 2021, respectively.

What's interesting is that there are no other door numbers aside from these sets of four digits. Itz Frolickz also points out how coincidental it is that the first number, 2013, happens to be the year GTA 5 was released. If the doors were following "regular" numbering, the door next to 2013 should have been either 2012, 2011, 2014, or 2015.

The fact that it jumps ahead to 2021, a full eight spots higher than 2013, is what raises the possibility of "Grand Theft Auto 6" releasing that year. Of course, there is a possibility that the door numbers are exactly what they appear to be; random.

2018, 2020, or 2021?

While there's reasonable support behind a 2018 release, more people seem to favor 2020. In fact, according to TechRadar, three years after "Red Dead Redemption 2" would make sense, given that it's been three years since GTA Online was released. Expert Reviews UK, however, says 2018 holds potential as well. "GTA: San Andreas" came out in 2004, with "Grand Theft Auto 4" following suit in 2008. "Grand Theft Auto 5" went live 2013, and since 2017 is the year of "Red Dead Redemption 2," we can expect another five year gap between GTA 5 and GTA 6.

Of course, seeing as Rockstar remains tight-lipped on the details, none of these speculations have been confirmed or denied. We'll just have to wait and see which guess is more accurate.