Quote Originally Posted by southshorepizza View Post
Is there a list of core files to update or do I need to do a full install if upgrading from a previous version. ...
Yes, every single file in the folder "1_modified_core_files". This is answered in the readme.

Quote Originally Posted by southshorepizza View Post
... I'm asking because if there are core files that were not updated in this newer version I would like not to spend time comparing them. ...
Depending on what version you are coming from the answer will be different. As mentioned the best way to find out is to compare the files from the version you previously had installed with the ones from the version you are trying to install.

But in the long run it is usually easier to just do a comparison directly between the files in "1_modified_core_files" and your installation. The "/admin/orders.php" file includes lines which indicate where changes were made specifically for "Edit Orders".

Quote Originally Posted by southshorepizza View Post
... The readme didn't really give any useful information on upgrades that I saw.
The readme has an entire section on how to install / upgrade this module. Edit Orders 4.1.x includes code to upgrade an existing 4.x installation when running the installation. There are no "special" instructions because there is nothing "special" one needs to do differently. Just the usual merge files, upload files, run the installer.