Updating WordPress to 4.9.18; main pane shows white screen;Fatal error line 188

Fatal error: Uncaught Error: Cannot use object of type stdClass as array in /home/jewishje/lizashtromberg.com/wp-content/themes/shopstar/functions.php:188 Stack trace: #0 /home/jewishje/lizashtromberg.com/wp-includes/class-wp-hook.php(286): shopstar_admin_notice('') #1 /home/jewishje/lizashtromberg.com/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #2 /home/jewishje/lizashtromberg.com/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #3 /home/jewishje/lizashtromberg.com/wp-admin/admin-header.php(255): do_action('admin_notices') #4 /home/jewishje/lizashtromberg.com/wp-admin/index.php(100): include('/home/jewishje/...') #5 {main} thrown in /home/jewishje/lizashtromberg.com/wp-content/themes/shopstar/functions.php on line 188

Notice: ob_end_flush(): failed to send buffer of zlib output compression (0) in /home/jewishje/lizashtromberg.com/wp-includes/functions.php on line 3783

Occurred after site updated to WordPress 4.9.18.

The site is live, but the WordPress backend Dashboard and all other pages do not display on the main pane. The WordPress navigation displays, but nothing on the right main pane.

Please help.

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