> I think a better idea would be to steal from DNS and use TTL and serial numbers (maybe just standard http last-modified is enough?) HTTP already has an Expir

> I think a better idea would be to steal from DNS and use TTL and serial numbers (maybe just standard http last-modified is enough?) HTTP already has an Expires header: https://tools.ietf.org/html/rfc7234#section-5.3 https://tools.ietf.org/html/rfc7234#section-5.3