To 9.0: Upgrade Android 4.4.2

: This usually voids warranties and can "brick" your phone if done incorrectly. Why It's Difficult Unsupported Software

Android 4.4.2 was designed for phones like the Samsung Galaxy S4, HTC One M7, and LG G2. These devices have: upgrade android 4.4.2 to 9.0

: Most devices on 4.4.2 likely peaked at Android 5.0 or 6.0 officially. Google Help The "Unmanaged" Path (Custom ROMs) : This usually voids warranties and can "brick"