Builds (starting with r65) are Android 5.0 Lollipop only.
Builds (starting with r72) are Android 5.1 Lollipop only.
Builds (starting with r76) are Android 6.0 Marshmallow only.
KitKat is dead and the last stable release was r63, which you're free to use if you're still on 4.4.4.
Lollipop 5.0 is also dead, and the latest stable release was r71.
Lollipop 5.1 is tango down, the latest stable release was r75.
Flash the latest release in your recovery:
1 - Flash the bloody zip on your recovery
Official app support:
Got any questions that you couldn't find after searching?
Disclaimer to moderators:
Slight OT is fine, but when users decide to act stupid they should be dealt with with the appropriate means - its really annoying for me when OT turns crazy. Please put the warning/ban hammer anytime any of you think there's lack of respect and/or too much unwanted OT crap - but if it doesn't meet this criteria let the OT posts alone. Thank you.