How to compile an android app, with update on install?

Question

Android

There is a project that needs to be edited, it was sent in a zip archive (apparently a feature of android developers, git is no longer in vogue), when launched in android studio it gives an error: Gradle DSL method not found: 'apply()'
Possible causes: The project 'mapel' may be using a version of the Android Gradle plug-in that does not contain the method (eg 'testCompile' was added in 1.1.0).
Upgrade plugin to version 3.1.2 and sync project.
despite the fact that the plugin is set to this version in the gradle settings. I created a new project and transferred the sources and gradle settings, but after compiling the size of the old apk and the new one is different, and when I try to put a new application on top of the old one, it says "Application not installed".
How to build a project so that the old application does not need to be deleted?

Answer 1

Check signature. If there are no keys, then no way.