The USAF has around 500 F-15s; active-duty units operate F-15C/Ds while the Air National Guard squadrons are equipped largely with older F-15A/Bs.
The Multi-Stage Improvement II upgrade for F-15C/Ds adds APG-70 radar, AIM-120 AMRAAM capability, improved electronic counter measures equipment and the joint tactical information datalink system. The F-15A/Bs are gaining elements of the Multi-Stage Improvement II, as well as improved Dash 220E engines. Their radars are being upgraded to APG-63(V)1 standard that incorporates features of the APG-70. Due to its capabilities the F-15 has only been exported to its most trusted allies. Israel has three units that are all based at Tel Nof; one unit operates the 13 ex-USAF F-15A/Bs delivered to Israel after Desert Storm. Saudi Arabia received 96 F-15C/Ds and equip five squadrons. It is likely that F-15s serving with Israel and Saudi Arabia will receive all or elements of the Multi-Stage Improvement II upgrade.
Delivered from 1979 to 1996, the Japan Air Self-Defence Force procured a total of 163 F-15Js and 50 F-15DJs, all but 16 of which were manufactured under licence by Mitsubishi Heavy Industries. The F-15J/DJs are almost identical to USAF's F-15C/Ds, but lack the US tactical electronic warfare system and are therefore fitted with indigenous electronic warfare equipment. Japanese F-15 improvements include a radar and central computer upgrade, to a standard comparable to the USAF's Multi-Stage Improveent II F-15s. Other elements include upgraded electronic counter measures systems along with new forward-looking infra-red and infra-red search and track systems. With these modifications, the F-15J will have the capability to carry fire-and-forget beyond visible range air-to-air missiles and possess much more resistance to any future electronic warfare threat. Production modifications are targeted for FY04, and about 100 F-15Js are planned to be covered by the upgrade. The F-15J/DJs primarily equip eight fighter intercept squadrons - a seven F-15DJs also serve with an aggressor unit.