HTC One M8 received Android 5.0 Lollipop update last month, but without the Sense 7 UI, which debuted with the HTC One M9. However, according to a tweet from Mo Versi, VP of Product Management at HTC, the One M8 will receive Sense 7 UI with the next software update.
@MohammadAsad528 no, this won't but our next update will include it. Thanks.
— Mo Versi (@moversi) April 7, 2015
HTC Sense 7 comes with improvements to BlinkFeed news reading interface, an extensive theming tool, new multitasking UI with pinch-to-zoom controls, option to add pull down notifications tab in the navigation bar, and slight changes to icons.
HTC has already released the One M8 and the One M7 with Android 5.0 Lollipop update, and will soon rollout the update to the One E8, Desire EYE, and the Desire 816.