RFC 1939, "Post Office Protocol - Version 3", May 1996Source of RFC: Legacy
Area Assignment: app
Errata ID: 4852
Reported By: Claude SIMON
Date Reported: 2016-11-02
Rejected by: Barry Leiba
Date Rejected: 2019-04-30
Section 3 and app. A says:
Section 3 : Responses may be up to 512 characters long, including the terminating CRLF. Appendix A : - specifies a status indicator length limitation of 512 octets, including the CRLF.
It should say:
What is written in appendix A does not match with what is written in section 3.
I guess both are wrong. The length of 512 may not concern the length of an entire response, and also not the length of only the status indicator, but the length of the first line returned as an answer by the server, which contains the status indicator, but sometimes some other text too (and, of course, is terminated by CRLF).
As I'm not sure that my guess is correct, and also because I'm not very comfortable with the English language, I am not able to propose a corrected text.
The text is correct as written, in that a single-line response is limited to 512 octets (which is also 512 characters in US-ASCII). The subsequent paragraph in Section 3 explains multi-line responses.