Firefox install old addons help

Linux and Unix-Like UNIX and Linux Applications
1

Can anyone tell me why the installing old addons method by changing the install.rdf max version is not working with Tab Mix Plus? I changed the maxVersion to both 17.* and 17.0. I get the error message:
Tab mix plus could not be installed because it is not compatible with firefox 17.0.

https://www.techsupportalert.com/content/how-update-firefox-thunderbird-addons-n
How to install �old� add-ons on Firefox 5. The easy way! | Computer Borders

2

F17 broke a lot of add-ons. Evidently, a new version of Tab Mix Plus is scheduled to be released January 2013.

See https://addons.mozilla.org/en-US/firefox/addon/tab-mix-plus/?src=search

3

I know. I was able to fix every other one of my addons with the install.rdf trick of changing the maxversion. I wanna know why tab mix plus is the only one that trick won't work on.