diff --git a/Koha/Patron.pm b/Koha/Patron.pm
index d1acc9ea09..394d3f070b 100644
--- a/Koha/Patron.pm
+++ b/Koha/Patron.pm
@@ -3338,7 +3338,7 @@ sub notify_library_of_registration {
     my ( $self, $email_patron_registrations ) = @_;
 
     if (
-        my $letter = C4::Letters::GetPreparedLetter(
+        my $letter = GetPreparedLetter(
             module      => 'members',
             letter_code => 'OPAC_REG',
             branchcode  => $self->branchcode,
@@ -3361,7 +3361,7 @@ sub notify_library_of_registration {
                 || C4::Context->preference('KohaAdminEmailAddress');
         }
 
-        my $message_id = C4::Letters::EnqueueLetter(
+        my $message_id = EnqueueLetter(
             {
                 letter                 => $letter,
                 borrowernumber         => $self->borrowernumber,
diff --git a/Koha/REST/V1/Patrons.pm b/Koha/REST/V1/Patrons.pm
index 05ae08688e..a6f9fb6657 100644
--- a/Koha/REST/V1/Patrons.pm
+++ b/Koha/REST/V1/Patrons.pm
@@ -160,6 +160,13 @@ sub add {
                     }
                 }
 
+                my $notify_library = C4::Context->preference('EmailPatronRegistrations');
+                if ( $overrides->{opac_reg_yes}
+                    || ( $notify_library && !$overrides->{opac_reg_no} ) )
+                {
+                    $patron->notify_library_of_registration($notify_library);
+                }
+
                 if ( C4::Context->preference('EnhancedMessagingPreferences') ) {
                     C4::Members::Messaging::SetMessagingPreferencesFromDefaults(
                         {
diff --git a/api/v1/swagger/paths/patrons.yaml b/api/v1/swagger/paths/patrons.yaml
index 6ec12ddedf..7257bc1798 100644
--- a/api/v1/swagger/paths/patrons.yaml
+++ b/api/v1/swagger/paths/patrons.yaml
@@ -435,6 +435,8 @@
           enum:
             - welcome_yes
             - welcome_no
+            - opac_reg_yes
+            - opac_reg_no
         collectionFormat: csv
     consumes:
       - application/json
diff --git a/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/opac.pref b/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/opac.pref
index ed9bd02d00..eb974797a8 100644
--- a/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/opac.pref
+++ b/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/opac.pref
@@ -912,6 +912,7 @@ OPAC:
             - '<br>If you choose <a href="/cgi-bin/koha/admin/preferences.pl?op=search&searchfield=EmailAddressForPatronRegistrations">EmailAddressForPatronRegistrations</a> you have to enter a valid email address: '
             - pref: EmailAddressForPatronRegistrations
               class: email
+            - '<br><strong>NOTE:</strong> This uses the OPAC_REG notice.'
         -
             - pref: PatronSelfRegistrationAlert
               choices: