diff --git a/CHANGES b/CHANGES
index 3996b7e4be..28f1ddcebd 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+3430.	[bug]		win32: isc_time_formatISO8601 was missing the
+			'T' between the date and time. [RT #32044]
+
 3429.	[bug]		dns_zone_getserial2 could a return success without
 			returning a valid serial. [RT #32007]
 
diff --git a/lib/isc/win32/time.c b/lib/isc/win32/time.c
index fe303f3732..8aaf6bc65f 100644
--- a/lib/isc/win32/time.c
+++ b/lib/isc/win32/time.c
@@ -313,7 +313,7 @@ isc_time_formatISO8601(const isc_time_t *t, char *buf, unsigned int len) {
 		GetTimeFormat(LOCALE_NEUTRAL,
 			      TIME_NOTIMEMARKER | TIME_FORCE24HOURFORMAT,
 			      &st, "hh':'mm':'ss", TimeBuf, 50);
-		snprintf(buf, len, "%s%sZ", DateBuf, TimeBuf);
+		snprintf(buf, len, "%sT%sZ", DateBuf, TimeBuf);
 	} else {
 		buf[0] = 0;
 	}