The following is the Nov. 3, 2021, Congressional Research Service report: Air Force F-15EX Eagle II Fighter Program.
From the report
On March 11, 2021, the U.S. Air Force took delivery of its first F-15EX Eagle II fighter. The Eagle II program is intended to deliver 144 aircraft to replace aging F-15Cs, most of which are in the Air National Guard.
The Trump Administration’s FY2020 budget proposal included a request for $1.1 billion to buy 8 F-15EX aircraft, the first procurement toward a planned...
https://news.usni.org/2021/11/04/report-to-congress-on-f-15ex-eagle-ii-fighter