Not official but it comes from a fairly credible source and the COD cakesocking YouTuber's have jumped on it. These 'leaks' happen every year but not usually this early so I can only assume with the huge influx of players returning to Black Ops on the XB1 and PS3 and with WW2's popularity nosediving; Activision have pulled their predicatable PR piece where somebody in the gaming industry/community leaks all the fringe details of the upcoming game. They haven't used Drift0r this time around though as that would be far too suspicious but it's still the same old marketing - gathering early hype when interest is waning in the franchise and masking it as some major internal leak of sensitive info.
If Marcus Sellars is to be believed and there's probably not too much reason not to; Black Ops 4 is modern, BOTG and will also appear on the Switch. All pretty viable and it ties in with other rumours. We'll see though https://gamerant.com/call-of-duty-2018-black-ops-4-rumor/