InfoPath Dev

I had a form that is signed digitally by administrator and published it to infopath form.Now,i need to do some changes to that template.So,i have published the template from sharepoint into my local mahine and started doing changes.I just found out,when i open form options-->security and trust-->the form is set to full trust but no certificate was created.Now,my question is ,after completing my changes,if i log as administrator and create the certificate again and publish that form back to  same location from where i have taken this template,does it pose any problems to the existing forms in that same location ?

 there should be no problem with your old forms, if you have not deleted/created new fields and have used the new fields in rules,data validations or coding...

Thanks for answering Qazi.I had new fields in my changes.I added few textboxes with some rules.But not edited any of the exisiting datasource.So,will that cause any problem.It is ok if the new textboxes won't refelect in the old forms.