As part of in-store promotion Konami is distributing Metal Gear Solid V: The Phantom Pain pamphlets in Japan.
They don’t contain a whole lot of new information, but do confirm (as was pointed out by a journalist during the Preview event) that Outer Ops (or at least something similar) will return in MGSV.
On Reddit, user hecheff translated some of the text.
Obtain people and resources in the field to expand your Mother Base. Expanding Mother Base allows all sorts of new weapons and items to be developed; starting with the ones found during missions, along with all sorts of support. You can also train soldiers and send them off into missions.
Additionally, you can intrude other players’ customizable Forward Operating Base (FOB).
An Open-World METAL GEAR SOLID, a great evolution
Realistic infiltration missions in an Open World
The massive field portrays a realistic passage of time and weather, allowing you to freely form missing strategies to pull off. You can also call on your buddies for support during missions. Capture soldiers, animals, vehicles, weapons, containers, etc. and clear missions to expand your Mother Base.
A Massive Field 200-times larger than “MGSV:GZ”
The explanation of the ‘Forward Operating Base’ makes it appear as though you actually won’t be able to attack other peoples’ entire Mother Base, but only this ‘FOB’. Maybe it’s a precaution to make sure players can’t get ruined because their entire base is looted.
Source: Metal Gear Japan Twitter, @waao353, kaikaikaisause on Reddit, JunkerHQ 1, 2