Error even when updated: Deprecated: Methods with the same name as their class..

-- HikaShop version -- : 4.0.
-- Joomla version -- : 3.8.13
-- PHP version -- : 7.2.1.0
-- Browser(s) name and version -- : Chrome
-- Error-message(debug-mod must be tuned on) -- : Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; plgHikashopDeleteCart has a deprecated constructor in /www/doc/www.elody.cz/www/plugins/hikashop/DeleteCart/DeleteCart.php on line 17

Hello,

Today I renewed my Hikashop subscription as to as I can update Joomla, PHP version and Hikashop.
It resolved many warnings, but I am still getting two errors:

On each Hikashop page:
Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; plgHikashopDeleteCart has a deprecated constructor in ...../plugins/hikashop/DeleteCart/DeleteCart.php on line 17

And second is in checkout step:
Warning: A non-numeric value encountered in ..../templates/passage/html/com_hikashop/checkout/step.php on line 188

This is the line 188

echo $this->cart->displayButton($checkout_next_button,'next',$this->params, hikashop_completeLink('checkout&task=step&step='.$this->step+1),'if(hikashopCheckChangeForm(\'order\',\'hikashop_checkout_form\')){ if(hikashopCheckMethods()){ document.getElementById(\'hikashop_validate\').value=1; this.disabled = true; document.forms[\'hikashop_checkout_form\'].submit();}} return false;','id="hikashop_checkout_next_button"');

Hello Jereme,

Thank you so much.

You are right, it was the custom plugin. We disabled it and it works perfectly.

About the second problem, turning off checkout legacy resolved the warning. Thank you!

Filip