'ionic cordova build android' Generate old prj format/script

Hi all, i’ve a doubt, normally i use this cmd to generate android project
ionic cordova build android --buildConfig=build.json --debug

I see that the generated project use an old grandle version (3.x instead 5.x) and some obsolete configuration options like ‘compile’

every time i’ve to open prj with Android Studio and wait the automatic project updated & fix

why does this happen?