Ohodnoceno 5 z 5 hvězdiček

od franc dne Čer. 24, 2009 · trvalý odkaz

You have to open the xpi with e.g. 7zip, WinRar, Winzip etc. and edit the install.rdf.
Write:
3.*
where you find something like 2.*
Save the changes and zip it again to the xpi.
Now you can install it.
You also can use Mr. Tech Toolkit to disable the compatibility-check, but this is unclean.