diff --git a/README.md b/README.md
index 0681cc5..7b1aa55 100644
--- a/README.md
+++ b/README.md
@@ -270,7 +270,7 @@ conf.probe.target=/srv/statoolinfos/well-known/statoolinfos/foo.bar.org-metrics.
 # Default: ^(?<remoteAddress>[a-fA-F0-9\:\.]+) - (?<remoteUser>[^\[]+) \[(?<time>[^\]]+)\] "(?<request>([^\"]|\")*)" (?<status>\d+) (?<bodyBytesSent>\d+) "(?<referer>([^\"]|\")*)" "(?<userAgent>([^\"]|\")*)".*$
 conf.probe.httpaccesslog.pattern=
 
-# Custom datetime access log pattern (https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html#patterns).
+# Custom datetime access log pattern (https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html#patterns). The language ID is mandatory.
 # Default: dd/MMM/yyyy:HH:mm:ss Z|EN
 conf.prob.httpaccesslog.datetimepattern=
 
@@ -278,12 +278,12 @@ conf.prob.httpaccesslog.datetimepattern=
 # Example: pathfilter=/.*well-known.*
 conf.probe.httpaccesslog.pathfilter=
 
-# Custom error log pattern with Java regex.
+# Custom error log pattern with Java regex. By default, automatic detection.
 # Default Apache: ^\[(?<time>[^\]]+)\]\s\[(?<level>[^\]]*)\]\s(?<message>.*)$
 # Default NGinx:  ^(?<time>\S+\s\S+)\s\[(?<level>[^\]]*)\]\s(?<message>.*)$
 conf.probe.httperrorlog.pattern=
 
-# Custom datetime access log pattern (https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html#patterns).
+# Custom datetime access log pattern (https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html#patterns). The language ID is mandatory.
 # Default: dd/MMM/yyyy:HH:mm:ss Z|EN
 conf.prob.httperrorlog.datetimepattern=
 ```