mobile

I'm running 4.4.4 but want to go to 5.1. I did run 5.0.1 for a while but factory reset back to 4.4.4. I seem to remember that OTA updated fine from 4.4.4 to 5.0.1 even with custom recovery and root. However my phone is only showing the OTA for 5.0.1, do I need to upgrade to this I order for 5.1 OTA to show.