Hello,
I have a problem with ionic 3 and android 11 :
Execution failed for task ‘:app:compileDebugJavaWithJavac’
It seems that the file-transfer@4 and google-maps@4 plugins do not work with android 11.
What should I do?
update to ionic 7 and android > 11 
Thank you Cicilleju
but I have kept ionic 3 for several years which worked without daring to update to ionic 4 !
What document do you advise me to update easily from v 3 to v 7 ?
Unfortunately it won’t be an easy process 
There are several braking changes from version 3 to 7 and from Cordova to capacitor.
My suggestion is making a new ionic blank app and start copying step by step all your code and plugins, doing the refactoring where needed.
There is none, you need to create whole new project and move the code over. That’s the easiest way.