Proving whether software functionality has changed following a software change

A non-transitory computer-readable medium including instructions that, when executed by at least one processor, cause the at least one processor to perform operations for using a line-of-code behavior and relation model to determine software functionality changes, comprising:

• identifying a first portion of executable code associated with a first version of software for a controller and a second portion of executable code based on a delta file configured to change software on the controller to a second version;
• accessing a first line-of-code behavior and relation model modeling first symbols and first symbol relationships of the first portion of executable code;
• accessing a second line-of-code behavior and relation model modeling second symbols and second symbol relationships of the second portion of executable code based on the delta file configured to change the software on the controller;
• performing a functional differential comparison of the first line-of-code behavior and relation model to the second line-of-code behavior and relation model;
• and
• determining, based on the functional differential comparison, a status of functional equivalence between the first portion of executable code and the second portion of executable code.