1. Device implementation navigation keys MUST use a distinct portion of the screen, not available to applications, and MUST NOT obscure or otherwise interfere with the portion of the screen available to applications. 意思大概是說, 在app的畫面時, 必須顯示一個區塊來顯示navigation bar, 並且不能和app的畫面重疊
2. Device implementation MUST present a Menu key to applications when targetSdkVersion <= 10 and SHOULD NOT present a Menu key when the targetSdkVersion > 10. 意思是說, 當app開發所使用的Android版本較舊(<=10), 必須顯示Menu key 也就是HTC device上的海苔條, 若版本>10, 就無需顯示