diff --git a/CHANGELOG b/CHANGELOG
index 737ce3a1efc..e7eb565c749 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -4,6 +4,7 @@ CHANGELOG Roundcube Webmail
 - Fix PHP warnings on dummy QUOTA responses in Courier-IMAP 4.17.1 (#6374)
 - Fix so fallback from BINARY to BODY FETCH is used also on [PARSE] errors in dovecot 2.3 (#6383)
 - Enigma: Fix deleting keys with authentication subkeys (#6381)
+- Fix invalid regular expressions that throw warnings on PHP 7.3 (#6398)
 
 RELEASE 1.3.7
 -------------
diff --git a/program/lib/Roundcube/rcube_vcard.php b/program/lib/Roundcube/rcube_vcard.php
index 75a24127b99..9138ba5fa38 100644
--- a/program/lib/Roundcube/rcube_vcard.php
+++ b/program/lib/Roundcube/rcube_vcard.php
@@ -525,14 +525,14 @@ public static function cleanup($vcard)
     {
         // convert Apple X-ABRELATEDNAMES into X-* fields for better compatibility
         $vcard = preg_replace_callback(
-            '/item(\d+)\.(X-ABRELATEDNAMES)([^:]*?):(.*?)item\1.X-ABLabel:(?:_\$!<)?([\w-() ]*)(?:>!\$_)?./s',
+            '/item(\d+)\.(X-ABRELATEDNAMES)([^:]*?):(.*?)item\1.X-ABLabel:(?:_\$!<)?([\w() -]*)(?:>!\$_)?./s',
             array('self', 'x_abrelatednames_callback'),
             $vcard);
 
         // Cleanup
         $vcard = preg_replace(array(
                 // convert special types (like Skype) to normal type='skype' classes with this simple regex ;)
-                '/item(\d+)\.(TEL|EMAIL|URL)([^:]*?):(.*?)item\1.X-ABLabel:(?:_\$!<)?([\w-() ]*)(?:>!\$_)?./si',
+                '/item(\d+)\.(TEL|EMAIL|URL)([^:]*?):(.*?)item\1.X-ABLabel:(?:_\$!<)?([\w() -]*)(?:>!\$_)?./si',
                 '/^item\d*\.X-AB.*$/mi',  // remove cruft like item1.X-AB*
                 '/^item\d*\./mi',         // remove item1.ADR instead of ADR
                 '/\n+/',                 // remove empty lines