The HTC One M7 dual-SIM variant, which was launched in the August 2013, is now receiving the Android Lollipop update. It is not confirmed if the update is rolling-out globally, or in selected regions.
The 675MB OTA update brings important enhancements and bug fixes including, enhanced lock-screen and notification panel, search function in settings, and obviously Android 5.0. After updating to latest software, the One M7 dual-SIM handset will run software version 7.17.720.6.
The update may or may not come to your device depending on your region. Luckily if your region is getting the update, just relax and wait for the update notification. Before starting the download, make sure your phone has 50% battery life and you are connected to Wi-Fi network to minimize data charges.