Do I need to upgrade to the next version of the Firefox browser?

Q I have used the Firefox web browser for the past couple of years. I have applied numerous add-ons and tweaks and am happy with the way everything works.

Recently, though, when I launch the browser I am met with a large graphic that warns: ‘This is an outdated version of Firefox’. A link is offered to a free upgrade to Firefox 4, and the message recommends that I should do this for security and performance reasons.

The last time I upgraded Firefox (I think from version 3 to 3.6), several of my add-ons no longer worked and other new quirks surfaced. As a result, I’m now a student of the ‘if it ain’t broke, don’t fix it’ school of thought.

I have no desire to change my current browser setup, as everything works just the way I want it. However, I’ll admit that I am concerned about the security warning (not to mention a little annoyed by its regular appearances). Should I be worried?
Derek Nelson

A It is up to the individual to decide the level of risk with which they are comfortable. While there is certainly some risk attached to using older (or ‘outdated’) applications, we wouldn’t worry unduly about continuing to use Firefox 3.6.

This is because there is risk attached to using any application – old, new, web browser, office suite or game. Password-protected documents created using Office 2003, for example, might be more easily cracked than those using Office 2010’s password tools.

However, only a fool would believe that the latest version of Microsoft’s office suite is completely secure: there are plenty of tools able to crack passwords applied to Office 2010 documents.

Similarly, an older version of a web browser, such as Firefox 3.6, will have more known security holes than the most recent version. There is therefore an undeniable risk in continuing to use Firefox 3.6 rather than updating to Firefox 4.

But Firefox 4 has already received a security update to fix various flaws, two of which were ranked as critical vulnerabilities. These could allow malicious websites to run code that would install software, requiring no user interaction beyond normal browsing.

Considered another way, for several months Firefox 4 users have unknowingly been relying on a web browser that contained two serious security holes. So there is undeniable risk using Firefox 4 too.

There are also potential compatibility problems, as alluded to in your question: you didn’t say which add-ons you have installed but there is no guarantee that all will have yet been updated to work properly with the latest version of Firefox.

Essentially, we are trying to reassure you that it’s probably OK to continue to using Firefox 3.6 for a while yet. Come back and ask us the same question in a year or two, though – when further and more serious security holes have been revealed and web technology has moved on – and we might give a different answer.

We are also compelled to say that from a security perspective, it probably is safest to update to the newest version. But as before, you must decide the level of risk that is comfortable for you. If it helps, some members of the Computeractive team continue to use Firefox 3.6 in preference to version 4.

In the meantime, it’s possible to stop Firefox 3.6 nagging you to update to Firefox 4. To do this, first open the Tools menu and choose Options. In the Options dialogue box, click the Advanced button and select the Update tab.

Now click to remove the tick from the Firefox box below the ‘Automatically check for updates to’ label. Click OK. When the browser restarts, the reminders to update will be history.