What is required to be IRI compliant?

[Stephane Bortzmeyer]

On Mon, Dec 28, 2020 at 02:54:14PM +0100,
 Solderpunk <solderpunk at posteo.net> wrote 
 a message of 22 lines which said:

> it's still possible for the server and client to have different
> ideas about how a hostname or path are represented, right?  With one
> using a composed form and the other a decomposed form?

Not right. RFC 5891, the standard for IDN, states that "By the time a
string enters the IDNA registration process as described in this
specification, it MUST be in Unicode and in Normalization Form C (NFC
[Unicode-UAX15])." So, at least the hostname has no problem.

gemini://gemini.bortzmeyer.org/rfc-mirror/rfc5891.txt