Does Your Android Phone Need an Antivirus App? - How-To Geek On the other hand, you may need to download an antivirus app if you use Android devices without the Play Store, sideload APKs from untrustworthy sources, or have an old, outdated version of Android. If that sounds like you, an app such as Bitdefender or Norton 360 may be useful. The moral of the story is you don't need an antivirus app on ...