Android 5.0 update notification appeared for sometime.

[Android Question]

Hi,

I got Android 5.0 system OTA notification on my Nexus 4 at 1am, but I didn't update it because I wanted to have a steady 3G network and once I reached office in the morning ,I observed that the Update notification vanished.

After performing "Check For Updates" from settings ,I am getting the message that my phone is upto date.

I have Kitkat version running on my phone.

Any pointers will be highly appreciated.

Thanks,
Girish