doc: update description of NTP over PTP in FAQ

diff --git a/doc/faq.adoc b/doc/faq.adoc
index 386f452d661ed35c0ed3e64669673e4309dc9952..85e56578847e38f3fdd59ead1afdaa9c5b5418a1 100644 (file)
--- a/doc/faq.adoc
+++ b/doc/faq.adoc
@@ -651,7 +651,10 @@ The `ethtool -T` command can be used to verify the timestamping support.
 As an experimental feature added in version 4.2, `chrony` can use PTP as a
 transport for NTP messages (NTP over PTP) to enable hardware timestamping on
 hardware which can timestamp PTP packets only. It can be enabled by the
-`ptpport` directive.
+`ptpport` directive. Since version 4.5, `chrony` can also apply corrections
+provided by PTP one-step end-to-end transparent clocks to reach the accuracy of
+ordinary PTP clocks. The application of PTP corrections can be enabled by the
+`extfield F324` option.
 
 === How can I avoid using wrong PHC refclock?