Using 1.7 requires compiling with Android 4.4 (KitKat); currently using API XX

今天爆了这个错误：

Using 1.7 requires compiling with Android 4.4 (KitKat); currently using API 16

参考文档：
http://www.cnblogs.com/mengfanrong/p/3745475.html
今天编译一个project，我设置为api 14，可是编译报错：

Using 1.7 requires compiling with Android 4.4 (KitKat); currently using API 4

參考 http://stackoverflow.com/questions/22552199/unable-to-build-android-project-using-facebook-sdk-against-android-2-2-froyo
Using 1.7 requires compiling with Android 4.4 (KitKat); currently using API 8

Righ click on your project > properties > Java compiler > enable "project
specific settings" Set Compiler compliance level to 1.6 re Build your project



至于为啥之前编译其它project，都是ok的，就不明确了。