Seems doubtful. When I look at this page on the add-ons site, it tells me it isn't even available for my released version of Firefox 14: https://addons.mozilla.org/en-US/firefox/addon/red-cats-green-flavor/

I guess I will continue on with my current version of Firefox until they figure out how to get the Red Cats into V.14.

Hopefully the developer will update his her theme before Firefox 15.

(Corrected per the below.)

The Red Cats themes author is a she ;)

If you keep getting update prompts to a 15.0 beta build then you are likely using one of the Beta builds of Firefox 14.0 as the release in 14.0.1 (there was no 14.0 as it was taken by mobile Firefox 14.0 earlier on). The release channel would not give updates to Beta builds.

Her homepage list the themes and versions they are compatible with http://www.bluecatsgraphics.com/Firefox_Themes/cats/

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http://forums.mozillazine.org/viewtopic.php?f=48&t=480063
http://forums.mozillazine.org/viewtopic.php?f=48&t=538590

Red Cats (green flavor) 5.6.0 beta 2 for Firefox 14 - 17:

http://forums.mozillazine.org/viewtopic.php?p=12229181#p12229181

Red Cats (blue flavor) 5.6.0 beta 2 for Firefox 14 - 17:

http://forums.mozillazine.org/viewtopic.php?p=12229199#p12229199