Spec says codepoint, implementation says grapheme

[lolbinarycat]

The spec says everything past the first codepoint is ignored, which would prevent the use of ZWJ sequences, but the implementation seems to respect multi-codepoint graphemes.

[robb]

A Open Heart message should contain of a single emoji sequence. However, the emoji sequence may be followed by arbitrary data which the server is expected to ignore.

Which is meant to follow the semantics here
https://www.unicode.org/emoji/charts/emoji-sequences.html.

I agree that grapheme cluster is a less ambitious way to phrase this.

Also, since the server is free to reject any emoji with a 400, we should point out that they may also want to consider an upper limit on ZWJs.