Brian kent

since the up date to WordPress 4.3 I no longer have WordPress dashboard and lots of error messages at the top of my website

instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Warning: Cannot modify header information – headers already sent by (output started at /home1/brian/public_html/wp-includes/functions.php:3457) in /home1/brian/public_html/wp-includes/pluggable.php on line 1207

Website is https://www.lamangaclubvisitorsguide.info/ Any help greatly appreciated
Brian

since the update to WordPress 4.3 i no longer have access to my WordPress dashboard and this message comes up when loading the website
Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home1/brian/public_html/wp-includes/functions.php on line 3457

Warning: Cannot modify header information – headers already sent by (output started at /home1/brian/public_html/wp-includes/functions.php:3457) in /home1/brian/public_html/wp-includes/pluggable.php on line 1207

My website is https://www.lamangaclubvisitorsguide.info grateful for any help cheers Brian