matrix-spec/content/rooms/fragments/v4-event-ids.md

---
---
{{% added-in this=true %}} The event ID is the [reference
hash](/server-server-api#calculating-the-reference-hash-for-an-event) of
the event encoded using a variation of [Unpadded
Base64](/appendices#unpadded-base64) which replaces the 62nd and
63rd characters with `-` and `_` instead of using `+` and `/`. This
matches [RFC4648's definition of URL-safe
base64](https://tools.ietf.org/html/rfc4648#section-5).

Event IDs are still prefixed with `$` and might result in looking like
`$Rqnc-F-dvnEYJTyHq_iKxU2bZ1CI92-kuZq3a5lr5Zg`.
Clarify event format text in room version specs (#3501) Split the text about event IDs and event formats into separate sections. This is largely to make it easier to link to, but I think the resulting text makes more sense too. 3 years ago			`---`
			`---`
			`{{% added-in this=true %}} The event ID is the [reference`
			`hash](/server-server-api#calculating-the-reference-hash-for-an-event) of`
			`the event encoded using a variation of [Unpadded`
			`Base64](/appendices#unpadded-base64) which replaces the 62nd and`
			63rd characters with `-` and `_` instead of using `+` and `/`. This
			`matches [RFC4648's definition of URL-safe`
			`base64](https://tools.ietf.org/html/rfc4648#section-5).`

Update documentation style & fix room version heading order (#3683) * Update documentation style & fix room version heading order Also add a missing signing key section to v6. This additionally contains various edits to the fragments to have them make a little bit more sense in context. Finally, this updates various aspects of the documentation style which haven't previously been considered - they're added here considering we're in the area. * changelog * enhanced changelogs * Minor wording adjustments * Apply suggestions from code review Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> 3 years ago			Event IDs are still prefixed with `$` and might result in looking like
Clarify event format text in room version specs (#3501) Split the text about event IDs and event formats into separate sections. This is largely to make it easier to link to, but I think the resulting text makes more sense too. 3 years ago			`$Rqnc-F-dvnEYJTyHq_iKxU2bZ1CI92-kuZq3a5lr5Zg`.