End-to-end encryption and privacy controls.
Message and call for free* around the world.
Group conversations made simple.
Say it with stickers, voice, GIFs and more.
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Swift(스위프트): 앱 최초 설치 후 한 번만 실행하는 작업, 버전 업데이트시에만 실행하는 작업 만들기 http://yoonbumtae.com/?p=4486