Hi Just saw this comment in the HISTORY file and noticed that the original and replaced values look just the same.
20170704 Typos (introduced: Postfix 2.10): in comments about IPv4-in-IPv6 addresses, replace :ffff::1.2.3.4 with the correct form :ffff::1.2.3.4. Incorrect or misleading comments are worse than no comments. Files: smtpd/smtpd_haproxy.c, postscreen/postscreen_haproxy.c. In the smtpd_haproxy.c file itself the new value is ::ffff:1.2.3.4 John