OS upgrades add platform versions
Major upgrades add platform features and APIs. A maker may promise a number of generations instead of a calendar date.
Security updates repair flaws
Security patches can continue after major upgrades stop, and cadence may change from monthly to quarterly.
Track both fields
Store OS-upgrade support and security-support end separately. Never copy one date into the other simply because only one promise was found.
Primary sources
Important
Device support and safety information can change. Recheck the linked manufacturer and regulator evidence before making a purchase or safety decision.