I worked for a software company years ago and we made the mistake of discontinuing products with a formal announcement. It never worked out because 1). it put our customers in play for our competitors, 2). it limited what we could do with those products (we actually had to un-discontinue or re-continue a few products to cover gaps in our product offerings), and 3). generally angered and confused our customers.

I think that the strategy followed is to provide an upgrade path with a solid story as to why your customers should move down that path, and then quietly stop working on the old products. While you can still get limited support for old phones, etc., notice that things like firmware upgrades and advanced drivers just are not around.