As of today, Lenovo 6000 Plus owners in India can finally enjoy Android Lollipop. The long-overdue OTA is currently seeding, so be sure to check for an update if you haven't received a notification yet.
The package itself is quite big at 1092MB, has a build number of A6000_A_0001_15_08_27 and is based on Android 5.0.2. As already mentioned, the A6000 Plus is a very popular device, especially in India. It was launched shortly after its sibling – the A6000 sold like crazy in a few consecutive online flash sales and has an equally tantalizing price tag and also double the amount of RAM at 2GB. Unsurprisingly, it did fairly well is sales as well.
As for the basic A6000, however, it is still stuck on Android 4.4 KitKat, which is slightly disappointing, especially considering the two devices are so alike in terms of hardware and compatibility shouldn't be a big issue. Still, there is hope, as Lenovo's official Android Update Matrix does state that the A6000 is also due for a Lollipop update by the endo of the month.
Thanks for the tip h4gr1d!