Well, we all know Bethesda loves giving us teasers and spoilers for Fallout 4 but still it's been six years. Bethesda revealed many teasers already take a look at this here.
So the first teaser is when a Bethesda employee was answering some fan question. A curious fan asked for a beta download code. Well the request was rebuffed, but the Bethesda employee did tell him the keep his guard on, because soon might be we will be getting some new about fallout 4.