Google launched Chrome Frame in 2009 as a way for businesses to move some of their web-based apps to a modern framework without having to switch away from Internet Explorer. Back then, Google argued that this would allow developers to target modern technologies for their users while still retaining compatibility with their legacy apps.
Chrome Frame allows developers to set a tag on their pages to automatically prompt Internet Explorer to switch to Chrome Frame or — if the user doesn’t have Chrome Frame installed — direct them to the installation page.
Chrome Frame will be retired in January 2014, when Google will cease support and updates for it.
The company, of course, recommends that businesses that rely on Chrome Frame switch to a modern browser or to check out Chrome for Business, which now includes legacy browser support through an add-on, too. Given that this is an open source project, there is always a chance that somebody else will pick it up and continue to support it.