Firefox and Chrome might break a bunch of websites thanks to a Y2K-like issue

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It seems once again the lack of forethought when setting up computer programs is going to haunt us. When Google Chrome and Mozilla Firefox hit version 100, an issue could break multiple websites, including some big names.

The issue? The “User Agent” string that websites use to identify the web browser that their visitors are using isn’t coded to use triple-digit identifiers. Yes, really. One of the most commonly used parts of the modern web can’t handle the number 100.

After all of the fuss with the Y2K bug, where computers could misinterpret the date 1 January 2020 as 1 January 1900; another coding error is about to wreak havoc on the internet.

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The worst part? It’s not like this hasn’t happened before, with the exact same browser identifier causing issues.

Back in 2009, User Agents went from single-digit numbers to double-digit ones. That change to version 10 broke Opera and Firefox; because websites thought they were using the out-of-date version 1.0.

So it seems everything that’s old is new again. The same out-of-scope coding issue is rearing its ugly head in both Firefox and Chrome.

The good news is that it’s actively being worked on. Mozilla has been testing for the issue since last summer, and Webcompat has an ongoing list of websites that aren’t compatible.

The bad news? That list includes websites from big names like Yahoo!, Standard Chartered, and Bethesda.

The “fix” for the issue that both Firefox and Chrome are implementing is to basically trick websites. If a website breaks on version 100, Mozilla will lie to it and say you’re on version 99.

Chrome takes it one step further and plans to freeze the major version at 99, and report the actual version number in a part of the “User Agent” that doesn’t affect websites.

Expect Chrome version 100 to arrive on March 29 and Firefox version 100 on May 3. We’ll see then how well the mitigation efforts work.

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Joe Rice-Jones

Maker, meme-r, and unabashed geek with nearly half a decade of blogging experience at KnowTechie, SlashGear and XDA Developers. If it runs on electricity (or even if it doesn't), Joe probably has one around his office somewhere, with particular focus in gadgetry and handheld gaming. Shoot him an email at joe@knowtechie.com.