Moving to 1.3.8a

I've been looking for answers to a few basic questions about upgrading and haven't been able to find definitive answers.

1. When upgrading from 1.3.7 to 1.3.8a, do I need to follow the same procedures as I would moving from a 1.2.X install to a 1.3.x install, or is it simply editing/adding some files to the 1.3.7 install.

2. If it's just some file editing/adding, where do I find those files? I've only found the security patches and the full 1.3.8a install.

3. If I have to install the full 1.3.8a package when upgrading from 1.3.7, will I need to apply all the security patches for 1.3.8/1.3.8a or are they included in the full install.

Thanks.

1. When upgrading from 1.3.7 to 1.3.8a, do I need to follow the same procedures as I would moving from a 1.2.X install to a 1.3.x install, or is it simply editing/adding some files to the 1.3.7 install.
   https://www.zen-cart.com/tutorials/index.php?article=98
   https://www.zen-cart.com/tutorials/index.php?article=108
   NOTE: best to upgrade a second install when running a live shop
2. If it's just some file editing/adding, where do I find those files? I've only found the security patches and the full 1.3.8a install.
   Not edits alone as you need the full release file set and the security patches
3. If I have to install the full 1.3.8a package when upgrading from 1.3.7, will I need to apply all the security patches for 1.3.8/1.3.8a or are they included in the full install.
   They are not and you will need to add them