Is my phone actually updated?

[AC Question]

I am a newbie to Android. I bought a Note 3 ATT from a friend of mine when my iphone broke. She said she wiped it clean before giving it to me.

It seems that my Note 3 may not be updated, I'm not sure if when she gave it to me it was to the current updated standards or if I am needing to do it now.

The first time I checked for an update it said there was one available. But the update said it didn't complete successfully. After that I had some apps that updated, but I can't seem to figure out if something has gone wrong.

Sometimes the phone seems to crash and move out of apps for no reason.

I commonly get an alert that says "Detection Information" "The device has detected an application attempting unpermitted actions. To protect your device, it is recommended you reboot". I have tried rebooting but always get the notification soon after.

When I look in settings-about device it shows this:
model SM-N900A
version: 4.3
baseband version: N900AUCUBMJ5


When I hooked it up to my computer with Kies 3 it says "this is the latest firmware"
Current firmware version: N900AUCUBMI9/N900AATTBMI9/N900AUCUBMJ5/N900AUCUBMI9

Isn't 4.3 Jelly Bean? Aren't we now on Lollipop? Am I updated? What should my version say?

If I am not updated, how do I update?

Sorry if this is very basic stuff...I have been searching online and the more I read the more confused I seem to be getting, so I figured I'd just put my specific question to a messageboard.

 

[Rukbat]

The 900A is AT&T, and the latest AT&T release is 4.4.4. But you won';t get it unless the phone is running on an active AT&T account.

You can get the 4.4.4 files at [ROM][1-25][ATT N900A][Stock][init.d][rooted… | AT&T Samsung Galaxy Note 3 | XDA Forums but you'll have to get the 4.2 to 4.4.2 update files and flash them first (unless you want to replace the ROM, not update it.) from [ROM][JULY 30][UrDroid][STOCK][AT&T NC2 … | AT&T Samsung Galaxy Note 3 | XDA Forums

If you flash the individual files, the phone should just update, if you flash the all-in-one file, it installs the ROM and overwrites all your apps, data, etc. You get a new, out-of-the-box ROM.