warning in custom page after upgrade to php 7.0

[aminp30]

Hi guys,

recently I upgrade my vb from 4.2.3 to 4.2.5 and my php to 7

now I have problem with my custom page. I had some errors with mysql codes
I changed theme to mysqli and issue solved. but still I have a warning:

PHP Warning: Illegal string offset 'styleid' in ..../includes/class_core.php on line 4732

what those it means and how to fix it?

[snakes1100]

Disable your plugins one @ a time till the error disappears, most likely one will need to be rewritten.

[aminp30]

Originally Posted by snakes1100

Disable your plugins one @ a time till the error disappears, most likely one will need to be rewritten.

I did it before. it's not related to plugins.

I can rewrite it but I don't know where is the problem