Chrome and Mozilla May Break Some Websites

Chrome, Firefox, and Edge will hit version 100 in a triple release that could break some websites. In the coming weeks, the move to version 100 could result in bugs or compatibility issues on some websites not ready to read triple-digit user-agent strings. Google, Mozilla, and Microsoft are busily preempting any significant problems.

Mozilla, Google, and Microsoft have warned about the upcoming version 100 release for months, which is about to drop in March for both Chrome and Edge, followed by Firefox in May. Mozilla and Google have been running experiments to test websites and report breakages. There’s a running list of issues, which is fairly small right now, and Engadget notes that the notable sites affected include HBO Go, Bethesda, and Yahoo.

While there are concerns around some websites breaking, a lot of hard work has been going on behind the scenes — much like what happened to avoid major headaches with the Y2K bug 22 years ago — to make the transition to version 100 go smoothly. Developers can enable a special flag in current Chrome, Edge, and Firefox versions to make the browsers report as version 100 and aid in testing sites.

When browsers first reached version 10 a little over 12 years ago, many issues were discovered with User-Agent parsing libraries as the major version number went from one digit to two. Much like the infamous Y2K bug that made the year 2000 indistinguishable from 1900 for some computers, browsers have different formats for user-agent strings. It is possible that some parsing libraries may have hard-coded assumptions or bugs that don’t take into account three-digit major version numbers.