diff --git a/content/appendices.md b/content/appendices.md
index 16995dc2..f9dbb455 100644
--- a/content/appendices.md
+++ b/content/appendices.md
@@ -689,12 +689,12 @@ However, the precise format depends upon the [room version
 specification](/rooms): early room versions included a `domain` component,
 whereas more recent versions omit the domain and use a base64-encoded hash instead.
 
+In addition to the requirements of the room version, the length of an event ID,
+including the `$` sigil and the domain where present, MUST NOT exceed 255 bytes.
+
 Event IDs are case-sensitive. They are not meant to be human-readable. They are
 intended to be treated as fully opaque strings by clients.
 
-The length of an event ID MUST NOT exceed 255 bytes.
-
-
 ### URIs
 
 There are two major kinds of referring to a resource in Matrix: matrix.to