Hello,
I noticed the widget constructor in /ad-injection/ad-injection-widget.php is still using the old format. WP core deprecated the old PHP4 constructors in July 2015, WP 4.3 (see notice: https://make.wordpress.org/core/2015/07/02/deprecating-php4-style-constructors-in-wordpress-4-3/)
It is a fairly simple fix that I’ve had to do myself on a couple of the sites I’ve worked on. Hopefully this is updated soon so I can get rid of the pesky WP errors at the top of the website I’m developing. 🙂
Thanks!
Emma
https://wordpress.org/plugins/ad-injection/