Just a heads up, plan your migration carefully. The best replacement (size, cutout, cost) is the PV800 4".
Free software with CCWB. Just like the PV300 Micro, the newer PV800 HMIs are made for small controllers.
But, there is no import of your existing HMI project file.
You will have to build your project from new.
You could use a PanelView Plus 7 and their new 4" terminal. It will let you import your existing project file, but it does not have serial ports and the project import is just as much work as creating a new project; PV300 Micro projects are usually very simple.
It's also more expensive, plus s/w $$.
FYI The PV800 and PanelView Plus have nothing to do with each other. Completely different software. So if you go down one path (ex. PV800) you will need new projects and software to use the other (ex. PVP).
Just like the other posts said, you need PanelBuilder. That will let you edit the project and see the tag addresses. I think it's better to use the PV800 and build a new project.
Hope that helps.