Nevermind updating, that process went horribly.

Maybe you guys can tell me specifically what changed from 1.6 on that would effect the bootstrap method opening a modal window. I purchased modal login plugin and the shortcode doesn’t trigger the modal. I noticed another post where someone was having the same type of trouble and it was fixed after they updated. Updating will not be an option for me so I need to know what change allowed it to work for the other guy please. Thank you

So, what would be your recommendation in my case. Here are the files which I have made mostly slight mods to over the past couple months of customization:

header.php
base.css
custom.css
layout.css
shortcodes.css
config-woocommerce/config.php
config-woocommerce/woocommerce-mod.css,
functions.php
functions-enfold.php
config-gravityforms/gravity-mod.css
single.php
single-portfolio.php
includes/loop-portfoilo-single.php
footer.php
page.php
index.php

I will definitely be avoiding this mess in the future by starting with child themes. I appreciate your help with this.