The official Security+OS update tracker page for Nokia smartphones has been updated on October 7 by HMD with details about the availability of September Security updates for all Nokia smartphones. As you may be already aware the page lists Build number and details like whether it is just a security patch or firmware update + security patch for a particular device.
As per the latest updated information provided on the page, currently, September Security update is available for all Nokia smartphones. None of the Nokia smartphones have however received the October security update.
In case the security update is not yet available for your Nokia smartphone, you should check the build number of your smartphone and confirm it with the information provided on the page. If the build number for a particular device is mentioned in the list then only it gets the update.
You can also click here for our detailed coverage of all software update news related to Nokia smartphones.