Version 11 might be the end of the line for Microsoft’s Internet Explorer, according to sources speaking to expert Microsoft analyst Mary Jo Foley. Instead of retooling the browser yet again for its next operating system and calling it Internet Explorer 12, Foley says that Microsoft will instead ship a wholly new Web browser with Windows 10, with IE11 riding along as a backwards-compatible alternative.

The new browser is currently under development at Redmond and has the project codename of "Spartan." A formal brand name for it has yet to be announced, but Foley notes that Microsoft employees mentioned in a Reddit AMA a few months ago that Microsoft had considered potentially discarding the "Internet Explorer" name and brand. That branding turns 20 years old in August 2015 and has two decades’ worth of mental associations and baggage—some of it positive, much of it extremely negative. It seems certain at this point that "Spartan," when it ships, will not do so under the IE brand umbrella.

According to Foley’s sources, Spartan will use both Microsoft’s Trident page rendering engine and its Chakra Javascript engine. However, the Trident being used by Spartan and the Trident being used by IE11 will almost certainly be different; Foley cites Neowin’s Brad Sams, reporting that Microsoft has forked Trident into two separate branches, likely so that it can maintain a stable legacy version for compatibility while actively developing the engine for the new browser.

Spartan is expected to be lighter and quicker than Internet Explorer 11; it will include proper extension support as well. It’s also supposed to come in desktop and mobile versions for inclusion with both the desktop and mobile versions of Windows 10. Foley speculates that Microsoft may give the public a peek at Spartan near the end of January with the next big Windows 10 reveal, but it’s unclear whether or not the browser will make it into the next Windows 10 Technical Preview.