Is there any official life cycle for Android versions in terms of which versions receive security patches each month?
If you look at the latest security bulletin it appears 8.0 is still receiving patches but I would like to know for how much longer that will be the case.
The table on this Wikipedia article lists all version prior to 9.0 as unsupported but the citations for these rows just link to the marketing site for that version of Android and I couldn't find any information about security patches there.
Note: I understand that actually getting updates to devices depends on manufacturers and carriers and is in no way guaranteed to match Google/AOSP, I'm just looking for official word from Google/AOSP on when they will stop pushing security bulletins to a given version of Android or a list of which versions are still supported other than just looking at the versions on the latest bulletin.