Firefox Add-on for Downloading the Right Version of Software

The other day, I was invited to a zoom meeting. Zoom is a video conference application also available for computers. It’s address is

When the time of our meeting came, I couldn’t hear anything when connecting from my Firefox browser, and saw the following message:


After a short IRC conversation on, I installed the User-Agent Switcher and Manager add-on on my Firefox.

This add-on adds an icon to the toolbar, Following is the icon as seen in the dark theme:

Now, when you click the icon, you will see the following popup:

Great! Now you can select a browser and operating system using the drop down lists, and then select the browser’s version using one of the radio button. Then, click the “Apply” button to save your changes and enable the add-on. Click the “Test” button to see what browser details will be passed to the remote server.

Good luck!


GUI Problems? Time to Upgrade Qt

Having upgraded my FreeBSD system and VirtualBox, I found that VirtualBox does not work when invoked from the window manager’s menu. So, I tried running it from the command line, and got the following message:

/usr/local/lib/virtualbox/ Undefined symbol “_ZNK6QColor6darkerEi@Qt_5”

I tried to search the web for the cause, and found a link to a compatibility report including added symbols. My symbol was nott found there, but at least I got a clue about what I had to do: upgrade Qt5.

From some reasons I’m not notified that it’s time to upgrade my Qt5.

I found a great option for command pkg:I

pkg version| grep qt5

The output reveals the current version of a package, and if there are later versions; following is a typical output line:

qt5-printsupport-5.12.2 <

The less-then symbols indicates that there is a more recent version.

I started upgrading Qt5 packages, first qt5-core, then qt5-gui and saw a little progress: new undefined symbols. Finally, VirtualBox started working.

Another application affected by the failure to upgrade Qt5 is VLC , the famous media player from

VLC does not show any error message, and you can run it from the command line with no problems. Specifying the path of the media device or file. For example by typing the command:

vlc cdda:///dev/cd0

if you want to listen to a compact disc.

Now, upgrading Qt5 has made VLC displaying its GUI window.