You will NEVER get a pre-release EOL notice from any semiconductor vendor, unless under NDA and you are a HUGE customer.
Intel/Altera tracks future orders, and when the projected orders fall below a threshold, they will EOL the part(s) or family.
I worked for a very large communications company, and we were regularly informed on technology going EOL (ie, not recommended for new designs) from virtually all vendors.
Any parts we designed in were committed under purchase contract to be available from the vendor for 7 years from our product FCS date.
So if you are a lone designer or a small company that buys parts say monthly thru distributors to meet product demand you are under the radar and down in the noise.
At this time however it almost does not matter. Unless you have locked in purchases from a year ago you likely won't see any parts this year.