Avaliado com 4 de 5 estrelas

Thank You Metal321.
To change the maxVersion still works with FF 43, but will not work with FF 44.

The real problem is that this add-on is not signed. According to timeline of the Add-ons/Extension signing Mozilla-wiki page:
https://wiki.mozilla.org/Add-ons/Extension_Signing

Firefox 40-42: Firefox warns about signatures but doesn't enforce them.
Firefox 43: Firefox will have a preference that allows signature enforcement to be disabled (xpinstall.signatures.required in about:config).
Firefox 44: Release and Beta versions of Firefox WILL NOT ALLOW UNSIGNED EXTENSIONS TO BE INSTALLED, WITH NO OVERRIDE.

Avaliado com 4 de 5 estrelas

This addon is very useful, and for many users. David White as release an update at https://addons.mozilla.org/en-US/firefox/addon/googlebar-fixed/ but never signed it. Now is this link dead :-(
Soon will Firefox (v44) not allow unsigned addons
What a shame for this irreplaceable addon.

Avaliado com 5 de 5 estrelas

to Long Pham. Please try with experimental version here : http://googlebar.mozdev.org/installation.html. Download it, then change maxVersion. It works for me.
But a upgrade is still welcome ;-)

Esta análise é para uma versão anterior do extra (0.9.15.14). 

Avaliado com 5 de 5 estrelas

I really like this addon. New version, 0.9.15.13, works very well with FF3.
For me the most useful addon, used every days.

Esta análise é para uma versão anterior do extra (0.9.15.13). 

Avaliado com 5 de 5 estrelas

FF3:
Download googlebar-0.9.15.11-fx+ns.xpi
Unzip & Edit instal.rdf
Change line 54 "2.0.0.*" with following
"4.0.0.*"
save install.rdf, zip it in googlebar-0.9.15.11-fx+ns.xpi,
Open FF3, Files, Open files, choose googlebar-0.9.15.11-fx+ns.xpi

Esta análise é para uma versão anterior do extra (0.9.15.11).