I currently have version 0.48 and am wondering if I should upgrade to 0.91. I have reservations because of seeing several posts about problems people are having. I do simple outline shapes.

If I do upgrade, is it installed leaving all docs as they were?

Any thoughts appreciated. TIA

I don't think you need to worry about upgrading. No one really should have any worries, as long as you get the stable version, and not a development version. 0.91 has fewer problems and more and/or better features than 0.48.

Unless you have some reason for wanting more than 1 version installed, you should uninstall 0.48, before installing 0.91. And no, it won't affect any of your existing files. They are stored in a different place than the program files, and aren't touched when uninstalling or re-installing.

Probably the reason you read about so many problems with Inkscape in this forum, is because there are so many advanced users here. Plus, that's why this forum is here, to help people with Inkscape problems. But for as simple as the work you describe, you may never run into any software problems. Although if you do, we'll be glad to help