You are S-Off, correct? If not, see my response above.
The firmware you'll need for the latest is 6.12.118.4 Or you could go superCID and flash WWE firmware
If you are S-On (or if you can't find firmware) visit this thread and read the instructions. You'll need the backup for your current firmware, plus the stock recovery for your current firmware version. You should be able to find that in your bootloader listed under "OS"
After you've done that you'll be able to update via official OTAs.
Thank you for the feedback!
Im actually S-On and was hoping I could get a firmware matching my mid and cid and avoid going back to stock and using OTA. Just followed the link you provided, and everything seems clear except how do I determine which stock recovery is for my device (btw. my hboot is 3.19): should I post the whole cmd "getvar" readout?
Also is it possible to determine if there actually are OTA updates for my device before I start the whole process?