Revisions

format 6
revision 6.0

Each revision of the specification has a number of the form 6.x and applies to file format 6.

Revision 6.0

Dated 2026-10-01. Applies to file format 6.

Revision 6.0 covers the format, its records, verification and operations: the file layout, the header line, the records and their kinds, the digest, the appendix, merge, diff and shard, the verify steps, canonical JSON, compression for transport, versioning and the conformance levels.

Amended 2026-10-06 in place, keeping the number 6.0: section 5.2 now states that kind names beginning with x- belong to applications, and section 16 lists the CSDT container format.

Read revision 6.0

How revisions are numbered

A revision that only clarifies the text, or adds OPTIONAL members, kinds or error kinds, is numbered 6.x.
A change that an unmodified version-6 reader would misread needs file format 7. There is no compatibility path between file format versions.
File format versions 1 to 5 are retired and have no readers.
Record kinds version on their own, through the record’s v member. Section 12.2
The error-kind list has its own version number; it is 1. Adding a kind adds conformance cases with it; removing or renaming a kind is a breaking change. Error kinds