I had Flat Awesome + 2.1 Beta 2 installed to begin working on some child themes. Just now, I downloaded the stable version from my account here. After copying the new files to the XF directory (overwriting the old files), I tried to install with the latest XML file, and got this:

Oops! We ran into some problems.​
The import could not be completed because the following issues were found:

This XML file is based on a newer version than you have installed. This may cause errors or unexpected behavior.

If you are sure you want to continue with the import, select the 'Skip import checks' option and try again.​

I also tried it as a new theme (not overwriting the 2.1 Beta 2 version), and even deleted and re-copied the files, but no change. Before I check anything further, was something in the XML file not updated, or is something else not in agreement? Or can I just go ahead and "skip import checks"?

The skip import is a new feature in 2.1, I believe it's to prevent accidents from happening.

Did you by chance rename Flat Awesome + (DO NOT EDIT) ?
No, I left the original theme alone, even the name. I haven't really started working on the theme other than creating nine child themes and adding a logo and background image to one of them (which I can export), so I may just completely uninstall and reinstall the whole thing rather than troubleshoot it.

So after I delete the theme from the Styles page in XF, I can just remove /styles/flatawesome and remove the installation that way to start clean?
If you want to submit a ticket I can definitely take a look so we can avoid it from happening in the future. I'll need an admin login with Appearance access.

Lastly just to clarify.... you are on the stable version of XF 2.1 correct?
No worries, @Russ -- I ended up wiping out the whole forum install and started fresh since I had some other issues. And it's all running fine now with the latest and greatest version of everything. I am thinking it might have been a botched upgrade to XF 2.1 stable at some point, as it has given me issues before on this particular server. Thanks for the reply!
To be fair, I was one of the first people to get this same error. The way I solved it was to import a new version of DO NOT EDIT xml, and make edits in child, or move the OLD child to the new XML.

I had XenBase 2, while @Russ shipped a fresh XenBase (with no "2" in it, or anything), so that's what caused the error prompt for me. Because xenForo thinks that the files are different. I brought it up to Russ to keep this in mind when doing new versions of XenBase, or another product that he wishes to release.
My setup of themes looks confusing to an outsider, but I usually have many child themes.

The DO NOT EDIT version is of course never touched. Below that I make an overall "master" version of that for the set of theme, and I usually don't touch that one either, except maybe for site-wide branding. In the third level of child themes I have each individual style (so for FA+, there's Stock, Adara, Zipped and Dark). I edit those individual styles for layouts, spacing, typography, etc. only. Finally, I make a fourth level of child themes below those which I use only for color variations. It is so much easier for me to do it this way, as it saves a lot of duplicate work. So out of my 11 child themes and sub-themes, only three or four might end up being public.

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