Slider Plugin 5.4 isn't working with word press engine php update 7.2

I just purchased rev slider 5.4 and tried to upload to site. Below are part of the error logs. Received . Is there an update or a fix? Otherwise, I want a refund. Let me know. Thank you.

[Sun Mar 10 02:33:07.351936 2019] [php7:notice] [pid 15845] [client 43.251.16.143:39125] preventing possible attempt to enumerate users
[Sun Mar 10 05:49:55.560135 2019] [php7:error] [pid 18966] [client 94.23.255.34:25091] PHP Fatal error: Uncaught Error: operator not supported for strings in /nas/content/live/marinsymphony/wp-content/plugins/revslider/inc_php/framework/base_admin.class.php:72\nStack trace:\n#0 /nas/content/live/marinsymphony/wp-content/plugins/revslider/revslider_admin.php(157): UniteBaseAdminClassRev::addMetaBox(‘Revolution Slid…’, Object(UniteSettingsAdvancedRev), Array, NULL)\n#1 /nas/content/live/marinsymphony/wp-content/plugins/revslider/revslider_admin.php(68): RevSliderAdmin->addSliderMetaBox()\n#2 /nas/content/live/marinsymphony/wp-content/plugins/revslider/revslider_admin.php(40): RevSliderAdmin->init()\n#3 /nas/content/live/marinsymphony/wp-content/plugins/revslider/revslider.php(146): RevSliderAdmin->__construct(’/nas/content/li…’)\n#4 /nas/content/live/marinsymphony/wp-settings.php(303): include_once(’/nas/content/li…’)\n#5 /nas/content/live/marinsymphony/wp-config.php(71): require_once(’/nas/content/li…’)\n#6 /nas/content/live/marinsymphony/wp-load.php(37): require_once(’/nas/content/li…’)\n#7 /nas/content/liv in /nas/content/live/marinsymphony/wp-content/plugins/revslider/inc_php/framework/base_admin.class.php on line 72
[Sun Mar 10 05:49:59.269563 2019] [php7:error] [pid 18952] [client 94.23.255.34:25130] PHP Fatal error: Uncaught Error: operator not supported for strings in /nas/content/live/marinsymphony/wp-content/plugins/revslider/inc_php/framework/base_admin.class.php:72\nStack trace:\n#0 /nas/content/live/marinsymphony/wp-content/plugins/revslider/revslider_admin.php(157):

Hi,

Contact with your item author hope they will help you out from this issue.

Thanks!