Future of USAF F-15C/D and their replacement

As we all know, F-22 procurement was not sufficient to replace all current air superiority tasked F-15s in USAF.

As such 9 squadrons have been retained – 1 in USAFE, 2 in PACAF and 6 in ANG as well as a variety of special purpose squadrons (test, aggressor, tactics).

According to http://www.airforcemag.com/MagazineArchive/Pages/2007/March%202007/0307force.aspx the F-15C/D will be retained beyond 2025

How long are these jets expected to last beyond 2025 and more importantly what will replace them?