InfoPath Dev

 Please can someone help?

I am working with browser Form injected qRules7.2.

Can I add some custom codes to it?

Is there anything to change in current form to use custom code?

Even I have backup form, I feel worried for my current working form.

Here is a document that explains how to use qRules with custom code: http://www.infopathdev.com/files/folders/qrules/entry56111.aspx

 Thanks.

My current form includes sharepoint list secondary data connections.

Do I need to change those connections to xml?

No - you can use secondary data connections to lists, web services, etc. in forms with custom code & qRules.