What happens when the device timezone changes?¶

A universal timestamp can display a different local clock time without its real-world instant changing, while zone-less local records may become ambiguous.

Storage determines the effect¶

UTC or an offset-bearing value can be converted for London, New York or another zone while preserving the instant. A local wall-clock value such as 14:00 without zone cannot reliably identify which universal time was meant. Calendar items may carry their own zone or follow application display rules.

Reconstruct historical context¶

Automatic or manual settings, network/location information, travel and system change records can indicate the active zone. Do not assume the zone at seizure applied earlier. Daylight-saving gaps and repeated hours also require the event-date offset. Record UTC plus relevant local display where supported and mark uncertainty otherwise.