Since I started a few threads about speculation on specific model numbers I realised it was getting a bit messy, so now I'll try and keep all my speculation in one place!
To start with, based on what NPU have found in Chinese and Russian certification databases (which I can't find myself to verify), there appear to be some model codes which we've not seen phones for yet: TA-1132 and TA-1146 in China and TA-1139 in Russia. These numbers are different from any model we've seen launched so far in China, and as there only seems to be one model variant per model name (e.g. TA-1131 is the only variant of Nokia X7) then this suggests that TA-1132 and TA-1146 are new models. The TA-1139 could be a variant of the same model as TA-1132 or TA-1146, or it could be another entirely.
For your info, here are the Chinese certification databases I've found myself:
I can't the certification database for Russia (more correctly, the Eurasian Economic Community, so more countries than just Russia, like the EU is not only Germany).
Neither shows these numbers, which is why I don't know if we can trust the information from NPU.
There's a new model spotted in bluetooth certification: TA-1136. Difficult to know what this is yet though.https://launchstudio.bluetooth.com/ListingDetails/71526
Rumours and speculation ongoing about what might be the 8.1.
It was spotted on Geekbench, but apparently with a 710 Snapdragon SoC https://browser.geekbench.com/v4/cpu/10399086. Since this is the same chipset that the X7 uses in China there is speculation that this means the X7 will be called 81. Given the existing 8 has an 835 it would be bizarre for the next version to actually have lower performance! In fact I would expect the 8.1 to have better performance than the Sirocco. I hope that this is a piece of deliberate misinformation being spread by HMD for them to have fun with us ;)
However, the 8.1 does appear to be forthcoming because Google have leaked it's existence in the list of devices with support for ARCore: https://developers.google.com/ar/discover/supported-devices. Or this could be more deliberate misinformation! At least, the Google page doesn't say what the SoC is. Note that the list of Google Play certified devices doesn't yet list the 8.1: https://support.google.com/googleplay/answer/1727131?hl=en
Finally, there has been a sighting of the TA-1119 and TA-1128 certification for Taiwan. I can't find the address for the Taiwanese NCC database so can't confirm this news. There is speculation that these are the model numbers for the 8.1. However there are many other model numbers which we haven't yet seen launched.