I have a question regarding custom templates. I have created a child theme where I have 12 custom templates. My question is if I should or have to update my custom templates as well when I updated the Atahualpa theme?

It all depends on what happens in the update. If upi used index.php as teh basis of your templates and it changes then yea, you probably will have to change yout templates.

You do have a playground site you can test out updates on don't you?

Thank you very much for your quick respons. You confirmed what I thought. Yes I have a test site as well so I am OK. Just hoped to save some work . So I guess I just check the index.php file and compare with the custom files, or does it tell in the update info?

the change log may or may not tell you so I would do a quick compare.