Meta Gear Solid 5: Ground Zeroes and The Phantom Pain may have some small canonical inconsistencies with the rest of the series, something creator Hideo Kojima sees as somewhat inevitable.
Speaking to Kotaku, Kojima said MGS 5's position in the timeline - after Metal Gear Solid 3: Snake Eater, but before Metal Gear Solid (and, in fact, the original Metal Gear games, pre-Solid days) means it will probably contain details which don't gel perfectly with other titles.
"I'm pretty sure that the guys at Star Wars had the same issues. When you try to write something that was supposed to be in the middle there will be some inconsistencies when you go into very small details," he said.
"The most important part is writing something that is fun, something that is impressive, something that is better than it was before. So sometimes in the interest of doing this, of having a better experience, we sacrifice some consistencies in the story. I hope the fans and players understand this, but I need to write the best we can, even if there are some small discrepancies."
Metal Gear Solid 5 was confirmed as a two part release last week; Ground Zeroes is a prequel to The Phantom Pain and will be released separately.