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Inkscape 0.48 should run flawlessly on Windows 10. Although you'll be missing out on tons of new features, which have been added since 0.48.
Any version of Inkscape will open files made with any other version of Inkscape. I'd be interested to learn where you are hearing this rumor. Wouldn't that be pretty stupid for any software developer, to make a new version which can't open its own files?
What you probably heard was about this. Starting with Inkscape version 0.92, Inkscape's native DPI is 96. All previous versions of Inkscape used DPI of 90. If you don't know what DPI is, then this change probably won't matter for you.
What the change of DPI means, is that if you want to edit an SVG file, which you first created in a version before 0.92,
and the specific size of things in that file matter you need to (1) make a backup of the file, before you start to edit, just in case, and (2) scale everything in that file before you start to edit.
But don't worry about memorizing that, if you decide to upgrade Inkscape. Whenever you open a file that you made with an older version, Inkscape notices, and it presents you with a dialog right on top of the canvas, where you can't miss it. It explains what it's for, it offers to make a backup for you, and it offers a couple of different ways to do the scaling, if you think you need to.
So far, most people have not needed it. Or at least, we haven't had very many questions about it. Some examples of when size really matters are: you're sending your Inkscape files to a cutter/plotter, such as CNC, laser cutter, or several other technologies; or it's a technical drawing.
If you do need to scale some older files, and you don't understand the dialog, feel free to ask us for help
(In my experience, you have more to worry about with Windows 10 itself, than with Inkscape! I found Windows 10 to be so awful, I actually did revert to Windows 7!) (Just so you know, sometime in the first few days you have it running, it's going to shut down and lock you out, for 5 or 6 hours, while it goes to get updates. You'll get 15 seconds warning!) (Also, if you use message rules in Windows Live Mail, get ready to find a new email program. If you create any drawings in Inkscape, which are black drawings on a transparent background, get ready to look for a new image viewer. And unfortunately, it gets worse!
