SSL security for purchased themes...

I have a Shopify account but am not digging their themes to use. I am considering purchasing a theme from ThemeForest to upload and am curious if I should be concerned about the SSL. My question is: Does Shopify handle all SSL issues on their back end regardless of theme used OR does the theme I purchase need to have this built in? Secondly, will regular updates to the theme compromise this security?
Any answers and further considerations are much appreciated. Thanks!

Shopify includes a free SSL option which is fine for most businesses: https://www.shopify.com.au/ecommerce-solutions/free-ssl-certificate

The shopify theme on ThemeForest shouldn’t need to be “SSL Compatible”, they all should work fine.

If you choose to install an theme update down the track it should’t change anything to do with SSL,