Need Help to Verify the PLC program for RSLogix 5000

Need advice.
I am new to Rockwell's PLC.
I am using RSLogix5000 Ver. 8.52 and 16.00.
I need to knwo how to verify two offline program to see what is the program changes had done by the previous Engineer and why he do it like this.
Thanks.

If you installed it, under RsLogix5000 tools there is a compare utility. It works great. If you didn't, get your original discs and install, then use.

To expand a bit on muusic man's post, when you install RSLogix 5000, there are optional utilities that you can install along with 5000. The two that I typically install are the compare utility and the task monitor. And like muusic man said, you can install them from the original disk.

Once they are installed, you can access them within RSLogix 5000 from the "tools" dropdown menu.