According to the report, Android 5.1 will include the following changes: Silent mode added after missing on Android 5.0, General improvements in system stability, Improved RAM management, Fixes for sudden app closures, Improved battery management, Excessive consumption of network devices when used Wi-Fi fixed, Issues with wireless connections fixed, Problems with Okay Google function solved, Notifications problems solved, Some sound problems experience by certain devices fixed and Other improvements and changes.
Sounds like a rather ambitious update, perhaps worthy of the full decimal point jump. And yes, you should take this report with a grain of salt. But even though you're heading to your spice rack to open the Morton's salt, it doesn't mean that there isn't some truth to this report. If this update comes through in February, we don't expect Google to move on from the Lollipop moniker so quickly.
source: AndroidPIT via TechRadar