After eight months of stalling (in the hopes of improving relations with China), the U.S. has finally agreed to provide upgraded radar for Taiwan's 130 IDF (Indigenous Defense Fighter) jets. This will make these 1990s era IDFs more of a match for China's Su-27s and Su-30s. Taiwan needs all the help it can get at the moment.
Earlier this year, the Taiwanese admitted that their older fighters (F-5s, IDFs and Mirage 2000s) were not likely to do well against the newer Chinese Su-30s and Su-27s. Taiwan ran combat simulations and found that they would lose 2.8 Mirage 2000s and 1.7 IDFs (equipped with the older radar) for every Su-30 shot down. The newer models of the F-16 are considered a match for the Su-30, and Taiwan is trying to get more of them. China is trying to persuade the United States not to provide them.
The 60 elderly Taiwanese F-5s are no competition at all for the Su-30s, and were only considered useful against Chinese bombers or their MiG-21 clone (the F-7). The locally made IDF is, and this is no secret, a second rate F-16 replacement. The 56 French Mirage 2000-5 are expensive, and manpower intensive, to maintain.
The Taiwan Air Force is considering retiring the older, more difficult to maintain, aircraft, and put more resources into the more recent models. Taiwan wants to upgrade its 146 F-16A Block 20 fighters, which are some of the oldest F-16s still in service. Taiwan has on order 66 F-15C block 50/52 fighters, a sale which has been blocked by local politics, and Chinese protests, for years. But now, these orders are very likely to be filled.