A · Official date
The manufacturer or regulator publishes a specific date for the exact model or clearly defined family. The source, scope, and check date should be visible.
B · Policy-derived date
A duration such as seven years is combined with a documented start date. The calculation and assumptions must remain visible beside the result.
Estimated or unknown
When primary evidence is incomplete, a date should be labelled estimated or left unknown. A precise-looking date is not evidence by itself.
Primary sources
Important
Device support and safety information can change. Recheck the linked manufacturer and regulator evidence before making a purchase or safety decision.