diff --git a/mod/forum/lang/en/deprecated.txt b/mod/forum/lang/en/deprecated.txt
index b437f9f564a..90cbb6cb7b0 100644
--- a/mod/forum/lang/en/deprecated.txt
+++ b/mod/forum/lang/en/deprecated.txt
@@ -1 +1,2 @@
 subscribersto,mod_forum
+postmailinfo,mod_forum
diff --git a/mod/forum/lang/en/forum.php b/mod/forum/lang/en/forum.php
index 46584e8f8de..aa23a28aa16 100644
--- a/mod/forum/lang/en/forum.php
+++ b/mod/forum/lang/en/forum.php
@@ -390,9 +390,6 @@ $string['postbymailsuccess'] = 'Congratulations, your forum post with subject "{
 $string['postbymailsuccess_html'] = 'Congratulations, your <a href="{$a->discussionurl}">forum post</a> with subject "{$a->subject}" was successfully posted.';
 $string['postbyuser'] = '{$a->post} by {$a->user}';
 $string['postincontext'] = 'See this post in context';
-$string['postmailinfo'] = 'This is a copy of a message posted on the {$a} website.
-
-To reply click on this link:';
 $string['postmailinfolink'] = 'This is a copy of a message posted in {$a->coursename}.
 
 To reply click on this link: {$a->replylink}';
@@ -529,3 +526,8 @@ $string['yourreply'] = 'Your reply';
 
 // Deprecated since Moodle 3.0.
 $string['subscribersto'] = 'Subscribers to "{$a->name}"';
+
+// Deprecated since Moodle 3.1.
+$string['postmailinfo'] = 'This is a copy of a message posted on the {$a} website.
+
+To reply click on this link:';