Error In PHP Scrip

I am trying to make changes within the format tab of settings, when I click the save changes button, I get he following message:

Fatal error: Call to undefined function sanitize_text_input() in /home/xxx/public_html/xxx/wp-content/plugins/wp-imageflow2/wp-imageflow2.php on line 653

Any idea why? I have disabled other plugins to see if that was causing any problems and there was no change whether off or on.

Thank you for your help.

https://www.ads-software.com/plugins/wp-imageflow2/