Firefox & Chrome Approaching Triple Digit Version – Cause for Concern?
In the next few months, both Firefox and Chrome will reach their 100th version. Similar to the concern with the Y2K bug, the change from a two-digit to three-digit version number may cause issues with certain sites. The sites potentially impacted are those that rely on identifying the version for specific business logic.
Last year, Mozilla launched an experiment to see if version 100 would impact sites and recently published the results Version 100 in Chrome and Firefox – Mozilla Hacks – the Web developer blog. The change caused issues with rendering, parsing failures, 403 errors, and “browser not supported” messages. It impacted a small number of websites but some notable ones like HBO Go and Yahoo.
The issue is there isn’t a single User-Agent (UA) format. The UA is, “a string that browsers send in HTTP headers, so servers can identify the browser.” There may be hard-coded logic that doesn’t allow some parsing libraries to accommodate the new three-digit major version.
The two browsers went through this 12 years ago when version 10 was released, and they went from a single digit to two-digit version. It is expected the lessons learned back then and improvements in parsing logic will causing less issues when they both hit 100. Chrome is scheduled to release version 100 on March 29, 2022, and Firefox will follow about a month later May 3, 2022.
Both browsers have been testing to determine the extent of potential “website breakage.” They will continue to test leading up the release dates. Firefox has a mitigation strategy dependent on the importance of the breakage and the Mozilla webcompat team can hotfix broken websites using a site intervention mechanism. Chrome’s plan is to “use a flag to freeze the major version at 99 and report the real major version number in the minor version part of the User-Agent strings.”
Firefox and Chrome are asking for your help. You can configure your browser to report as version 100 today. If you are a website maintainer, develop a User-Agent parsing library, or are browsing the web and notice issues — details about how to configure the major version to 100 for testing, and where to report issues can be found in the web developer blog above.
This blog is a little outside my normal comfort zone, but as more solutions, including our software, are deployed through browsers it seemed like an appropriate topic.
