Internet Explorer legacy user agent
Internet Explorer is retired, but its user-agent patterns still appear. Older IE used an MSIE token; IE 11 dropped MSIE and is recognised by a Trident engine token instead. Today, genuine IE traffic is rare, so these strings frequently come from old devices, embedded clients, or bots imitating a browser.
The IE legacy UA patterns
Older Internet Explorer versions identified themselves with an MSIE token and a version number. IE 11 changed approach: it removed the MSIE token and is instead recognised by a Trident engine token (Trident being IE's layout engine), often alongside an rv: version marker.
So two patterns matter: MSIE for older IE, and Trident for IE 11. A rule that only checks for MSIE will miss IE 11 entirely.
- Older IE: an MSIE token plus a version
- IE 11: no MSIE token; a Trident engine token instead
- Trident is IE's layout engine, distinct from WebKit/Gecko
Why fresh IE traffic is suspicious now
Internet Explorer has reached end of life and its real-world usage is very low. When an IE-shaped user agent appears today, it is more likely to be an old or embedded client, a misconfigured tool, or a bot copying a dated browser string than a person browsing in IE.
Treat IE-shaped traffic as a weak, dated signal: match on the stable MSIE or Trident tokens, do not over-trust the claim, and corroborate with behaviour. Confirm token specifics against Microsoft's archived documentation.
How it appears in analytics and logs
A user agent with an MSIE or Trident token claims Internet Explorer. Because real IE usage is now very low, such strings are often old or minimal clients, or automation wearing a dated browser identity.
Diagnostic use case
Recognise legacy IE patterns by MSIE and Trident tokens, and treat fresh IE-shaped traffic with suspicion given that genuine IE is now uncommon.
What WebmasterID can help detect
WebmasterID recognises legacy IE patterns server-side and records a coarse browser category, while keeping unverified IE-shaped automation in an honest bucket rather than assuming a real IE visitor.
Common mistakes
- Checking only for MSIE and missing IE 11, which uses a Trident token.
- Assuming an IE-shaped string is a genuine person now that real IE usage is tiny.
- Mistaking the Trident token for a modern engine like WebKit or Gecko.
Privacy and accuracy notes
An IE user agent describes legacy browser software, not a person. WebmasterID stores a coarse browser category rather than a real visitor's raw string.
Related pages
- Browser user agents: how to read them
A browser user-agent string packs several tokens into one line: a legacy Mozilla prefix, a rendering-engine signature, the platform, and the browser itself. This page explains each part so you can read a UA without over-reading it, because the contents are client-controlled and can be copied by any client.
- Bot vs browser user agents: how to tell them apart
A user-agent string is a self-reported label, not an identity. This page explains how declared bots name themselves, why almost every UA still starts with the legacy Mozilla token, and how to read the difference between an automated client and a real browser without over-trusting the string.
- Bot vs human traffic
Separate real browser visits from dated or automated clients.
Sources and verification notes
- MDN — Internet Explorer / Trident user agent reference
- Microsoft — Internet Explorer user agent strings (archived guidance)
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.