You did not write about the time limited upgrade path to 3.9 and v4 in any newsletter!
Twitter, Facebook and your blog are as much helpful to me as pinning the news to your frontdoor. Either because I don't use them (Twitter, Facebook) or I don't visit your site frequently to get news like this.
And is it the customers "duty" or a matter of customer care to find out about these news?
To address your other point, RS, we did not send out a newsletter for this recent MAS promotion. This is something we are looking to improve going forward.