Need some help regarding RUU and OTA update topic

Okay so been some time since I've been on here and since I have got a oneplus one and I am selling my M7.

I was rooted and running tickdroid 8.0 I think it was, 4.2.2 as I didn't feel the hassle to update it etc.

Now I managed to get back to stock by flashing the stock RUU and my software currently stands at 4.1.2

I searched for an update but it says it's up to date? The phone has stock recovery etc I just want to update it to the latest firmware before I sell it. So any help to get it up to kitkat would be appreciated

Bootloader is relocked
Software 4.1.2
S-Off

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Now it has been some time since I've done this whole rooting thing etc but I managed to gain s-off last night and change to supercid so I could flash the stock

Also I can't seem to get any service? I've tried several sims

Any help

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