Android Studio
(Android Studio) Failure [INSTALL_FAILED_VERSION_DOWNGRADE]
SAFE
2016. 12. 26. 20:39
Failure [INSTALL_FAILED_VERSION_DOWNGRADE]
You're trying to install apk with a lower versionCode that is already installed.
출처 : http://202psj.tistory.com/799
해결 : 기존 스마트폰에 설치되어있는 기존 앱 삭제 후 다시 실행