Samsung has been continuously released the Android 5.0 update in more countries for its flagship devices and today the Company rolling out Lollipop for its dual-SIM version of Galaxy Note 4 Phablet. The device is exclusively available in China and Hong Kong and the firmware update is available on both regional models.
The update being rolled out Over-The-Air (OTA) and it weighs around 1GB. It brings new Lollipop Material Design UI, new notification system, the faster ART runtime, stability tweaks, bug fixes and much more. You should need at least 3GB free space on your phone memory to complete the firmware upgrade and after upgrading to Lollipop your phone memory will decrease minimum 950MB.
The update notification should automatically reach on your device. You can also check it manually by heading to Settings -> About Device -> Software Update.