What is Internet Explorer and why does it matter now
Internet Explorer was a web browser developed by Microsoft, first released in 1995 and retired in June 2022. It shaped enterprise work, web standards, and security expectations for nearly three decades. Understanding Internet Explorer explains how modern browsers, compatibility requirements, and legacy systems emerged. This profile is useful when you encounter legacy sites, old documentation, or support policies that reference IE behavior, rendering, or security features.
Key facts and verified timeline of Internet Explorer
| Date or Period | Event | Why It Matters |
|---|---|---|
| August 1995 | IE 1.0 shipped with Windows 95 | Marked Microsoft’s entry into the web browser market |
| 2001–2006 (IE 6–7 era) | Peak desktop market share; proprietary features | Drove web standards debates and compatibility challenges |
| 2015 | Microsoft Edge launched as the new default browser | Signaled the shift away from IE toward a modern rendering engine |
| June 15, 2022 | Official retirement and stop of support for Internet Explorer | End of security updates, compliance changes, and migration guidance |
Internet Explorer market share and adoption trends
IE’s share rose rapidly in the early 2000s, peaking above 90% for desktop browsers, then declined as standards-compliant competitors and mobile browsers grew. Its long tail in enterprise environments persisted because many internal tools were built for IE’s legacy rendering and JavaScript behavior, creating continued demand for compatibility despite the retirement date.
Technical profile: architecture, security, and compatibility
Core components and rendering
IE used proprietary components such as MSHTML (Trident) for rendering and Chakra for JavaScript. Later versions introduced partial standards support, but fundamental architecture diverged from open web standards, leading to inconsistent behavior across sites.
Security model and updates
IE received periodic security updates, primarily through monthly patch cycles. Microsoft’s Security Response Center published advisories and mitigations for vulnerabilities. In its final years, IE lacked modern sandboxing and mitigations found in contemporary browsers, which contributed to the decision to retire it.
Compatibility tools and document modes
IE included Enterprise Mode and developer tools to emulate older document modes, enabling legacy line-of-business applications to function. These tools are relevant when organizations plan migrations away from IE-dependent workflows.
How Internet Explorer compares to modern browsers
Modern browsers prioritize standards compliance, sandboxing, phishing and malware protection, and frequent updates. In contrast, IE’s architecture and update cadence made it more vulnerable to security issues and less capable of supporting current web technologies such as modern JavaScript frameworks and CSS features.
- Standards support: Modern browsers follow W3C and WHATWG standards more closely; IE implemented early, proprietary features that diverged.
- Security model: Contemporary browsers use process isolation, site isolation, and robust permission systems; IE relied on older security zones and fewer sandboxing features.
- Performance and updates: Current browsers receive frequent performance improvements and immediate security patches; IE’s updates ended with retirement.
- Mobile and extension ecosystems: Modern browsers support cross-platform extensions and responsive experiences; IE had limited, platform-specific add-ons.
Practical guidance for organizations and users
If you still rely on applications that require Internet Explorer, plan to migrate by using compatibility features in Microsoft Edge, such as IE mode, or by modernizing the applications themselves. For general web use, switch to a current browser to receive security updates and better performance. Evaluate internal tools, update legacy documentation, and validate functionality in alternative environments before decommissioning IE.
Internet Explorer in context: legacy, documentation, and migration
Internet Explorer is a significant chapter in web history, illustrating how browser markets, standards processes, and security expectations evolved. Many organizations still reference IE in policies, logs, and legacy systems. Understanding its role, technical constraints, and retirement timeline supports responsible migration and helps avoid continued dependence on an unsupported product.