Recent custom post widget

Just installed your recent custom post widget, seems to be causing some havoc, is it working? I got:

Notice: The called constructor method for WP_Widget in RcptWidget is deprecated since version 4.3.0! Use

__construct()

instead. in /srv/users/shalina/apps/shalina/public/wp-includes/functions.php on line 3916

Warning: Cannot modify header information - headers already sent by (output started at /srv/users/shalina/apps/shalina/public/wp-includes/functions.php:3916) in /srv/users/shalina/apps/shalina/public/wp-admin/includes/misc.php on line 1126