Fastmail Fastmail This specification defines version "2.0" of JSCalendar, a data model and JSON representation of calendar data that can be used for storage and data exchange in a calendaring and scheduling environment. This document obsoletes RFC 8984, also referred to as version "1.0" in this document. The newly defined version "2.0" aims to improve interoperability with existing iCalendar-based systems. It also aligns its definitions with JSContact, such as the IANA registry policy, validation requirements, and versioning scheme.