Android Question I want to upgrade a non-B4A App with a new B4A App

You need to get the original signing certificate and the package name for the APK that is already in the appstore. The filename is probably not the actual package name of the APK. You can get the existing package name by installing the existing APK and go into application manager and click on the app - the package name will be something like "com.company.appname" on that page.

Then set the new B4A app to use the same package name ("project....build configurations") and compile the B4A app using that original certificate.

Then you should be able to upload the new B4A APK to replace the existing one.

UPDATE: Also make sure the app version in the new B4A apk is HIGHER then the version of the existing APK

You need to use the same signkey like you used for the old app

Thanks for your help,
I could already change the name of the package, following its instructions, ?

but I didn't know how to change the signing key, (I don´t have access to the previous code)

now when I try to upload the new file .apk play.google console says:

You uploaded an APK file that is not signed with the upload certificate and you should use it. The uploaded certificate has the fingerprint
[SHA1: 73: AA: AA: A1: 16: 5C: B1: DB: FD: FB: 2B: 8E: XX: XX: XX: XX: XX: XX: XX: XX]
and the certificate you used to sign the APK has the fingerprint
[SHA1: DD: BB: BF: BB: 67: 57: 7C: E5: 57: 12: D9: 88: XY: XY: XY: XY: XY: XY: XY: XY]

Click to expand...

Regards,

Leo.

You don't need access to the original code, but you do need to get a copy of the original signing certificate.

If you can't get the original certificate, then the only thing you can do is post your new app under the same "App Name" as the old app, but you need to choose a different package name in order to upload the new APK into your google dev account. Then un-publish the old app so only your new app will be shown in your google account and on the playstore.

The downside of this is that existing users of the old version will not be notified that there is a new version available.

If App Signing by Google Play is enabled for your app then,

Goto Play Console > Choose you app > Release Management > App signing

You can download upload certificate from there. Then you can use java keytool to convert the .der file to .keystore

Also for the package name part it is worthy mentioning that the URL part of the web page of the app in Google play mentions it.

leonardo pino said:

I don´t have access to the previous code

Click to expand...

Sounds a bit like you are not the owner of this app.

Hi, thanks to all for your answer,

effectively this app is not mine, it's for a client,
He gave me access to the account where the app was uploaded,
another programmer made version 1 in another language.

I will follow your recommendations,

Regards,
Leo