Why I can't use low version buildTools?

Question

When I use 25.0.0, my project appear some bug(Floating Action Button doesn't show). But I can choice low version.

Error:The SDK Build Tools revision (24.0.3) is too low for project ':app'. Minimum required is 25.0.0

Answer 1

change classpath 'com.android.tools.build:gradle:+' to classpath 'com.android.tools.build:gradle:2.2.2' , and now ,I can use 24.0.3