ADB:INSTALL_ FAILED_ UPDATE_ Incompatible [solved]

installation encounters this

adb: failed to install xxxxxxx.apk: 
Failure [INSTALL_FAILED_UPDATE_INCOMPATIBLE: 
Package com.xxx.xxxx signatures do not match the previously installed version; ignoring!]

uninstall the app with the same package name and then install

adb uninstall com.xxx.xxxx


but looking at this discussion on Stack Overflow, it doesn’t seem to say what the problem is because of
link: https://stackoverflow.com/questions/31489567/manually-installing-an-updated-apk-fails-with-signatures-do-not-match-the-previ
ultimately find another q&a
https://stackoverflow.com/questions/49757862/install-failed-update-incompatible-package-signatures-do-not-match-the-previous?Rq = 1
said domestic a blog: https://blog.bihe0832.com/android-v2-issue.html
reason involves the jarsigner, don’t know why the company network temporarily can’t open it, see you later add study reasons.

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