Unable to install Mouseless Browsing from addons.mozilla.org in Firefox 19 and 20

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Install Firefox 19 or 20
2. Go to https://addons.mozilla.org/en-us/firefox/addon/mouseless-browsing/
3. Click "Add to Firefox"

What is the expected output?
Mouseless browsing addon should be downloaded and installed in firefox

What do you see instead?
Mouseless browing addon is downloaded but fails to install with the following 
message:
Mouselss browsing could not be installed because it is not compatible with 
Firefox 20.

What version of the product are you using? On what operating system?
Windows 7 64 bit

Please provide any additional information below.

I've also tried to link directly to the mouseless browsing addon using this 
link with the same result:
https://addons.mozilla.org/firefox/downloads/latest/879/addon-879-latest.xpi 

Installing through firefox add-on interface works fine though.

Original issue reported on code.google.com by liv.tesd...@gmail.com on 19 Apr 2013 at 9:43

[GoogleCodeExporter]

Looks like the problem is in the file install.rdf that is part of the xpi. Line 
23 says : <em:maxVersion>4.0b8</em:maxVersion> guess it should say 
<em:maxVersion>20.0</em:maxVersion> or something similar.

Original comment by ragna...@gmail.com on 19 Apr 2013 at 9:59