I have lost conficence of using ArgoUML in project

ArgoUML0.19.2 can't open the file created by ArgoUML0.18.1.It hited my heart again.Although,I am very like ArgoUML,but,my main goal is to learn UML,not a tool.If this tool has stop my learning UML and our project,I have to discard it saddly.

The real goal of ArgoUML is practicing technique,or proffering it to general user?

I think,a software is a good software only if it is used by many special user.