In this version (4.0.16) of your wonderful plugin 'captcha' is not working for me.
Plugin says the correct captcha is incorrect and repeat the same when we refresh captcha code. It doesn't recognize the correct captcha code anymore.
I've deactivated and reactivated the plugin after update and the problem remains.
I've had to disable captcha in security tab until it will be fixed.
Thank you for your support since now.