The update is available over-the-air (OTA) though users can manually check for the update via Settings > About Phone > System Update. The update is about 1.3GB in size, so we recommend users to switch to Wi-Fi before downloading the update. As per user reports (via PhoneRadar), the Lenovo A7000 is receiving the new update with build number A7000-a_S153_151127_ROW_TO_A7000-a_S223_160405_ROW.
Unfortunately, there is no official changelog to highlight the changes that are coming to the phone with the update. To recall, the Lenovo A7000 launched in India last April and came running Android 5.0 Lollipop, skinned with the Vibe UI. Last year, Lenovo had claimed to sell 1 million 4G-enabled smartphones in India which included the Lenovo A7000 smartphone apart from other Lenovo phones.
We do know that Android 6.0 Marshmallow (previously just Android M) brings features such as revamped app permissions; Google Now on Tap; Android Pay mobile payment system, and new fingerprint APIs for developers among others.
Last week, Lenovo launched the Phab smartphone-tablet hybrid, priced at Rs. 11,999. The dual-SIM (Micro-SIM + Micro-SIM) Lenovo Phab runs Android 5.1 Lollipop and features a massive 6.98-inch HD (720x1280 pixel) IPS display, which is the highlight of the handset.