Joomla 4.0 said goodbye to Internet Explorer!

Joomla and the end of Internet Explorer: the right call, fully vindicated

When Joomla! 4.0 shipped with Bootstrap 5 and dropped Internet Explorer support, it was a bold move that drew some grumbling from enterprise corners. In 2026, with Internet Explorer long since dead and buried by Microsoft itself, that decision looks not just correct but visionary. Here is why it mattered, what has happened since, and what it means for Joomla developers today.

TL:DR – If you are arriving at this article because someone in your organisation is still asking about Internet Explorer support: the answer is no, and it has been no for years. Point them to Microsoft's retirement announcement and move on. There is better work to be done.

The decision: Bootstrap 5 and the end of IE in Joomla

Joomla 4.0 adopted Bootstrap 5 as its front-end framework. That single dependency change made Internet Explorer support impossible — and intentionally so. Bootstrap 5 dropped IE entirely in the name of performance, cleaner code, and modern browser APIs. With Joomla 5 now firmly the current release line, that foundation has only been built upon further.

Bootstrap 5 brought several meaningful improvements that made the trade-off more than worthwhile:

• No dependency on jQuery — One of the most significant architectural changes in the framework's history. Projects built on Bootstrap 5 are lighter and faster as a result. Joomla still ships jQuery for extensions that need it, but the core no longer depends on it.
• No Internet Explorer support — A firm line in the sand, not a soft deprecation. IE is simply out of scope.
• JavaScript modernisation — The framework moved to vanilla ES6+ JavaScript, improving code quality and long-term maintainability.
• Redesigned form controls — Unified appearance and behaviour across operating systems and browsers, replacing the inconsistent patchwork that IE-era development required.
• CSS custom properties — Enabling far more flexible theming and customisation without the hacks that older browsers demanded.
• New Utilities API — A structured approach to extending Bootstrap via source files, giving template and extension developers a cleaner toolkit.
• Toggle buttons rebuilt — Powered by checkboxes and radio inputs rather than fragile JavaScript state, making them more reliable and accessible.

Microsoft made it official: IE 11 is gone

Any lingering doubt about whether dropping Internet Explorer was premature was erased on 15 June 2022, when Microsoft officially retired Internet Explorer 11. After more than 25 years, the browser was permanently disabled through a Microsoft Edge update on affected versions of Windows 10. Attempts to open Internet Explorer were redirected to Microsoft Edge.

Microsoft did provide a compatibility bridge for organisations with genuinely legacy internal tooling: Internet Explorer mode (IE mode) built into Microsoft Edge. IE mode allows specific, whitelisted URLs to render using the legacy Trident engine within Edge. It is explicitly a transitional tool for internal line-of-business applications, not a reason to build or maintain public-facing websites with IE compatibility in mind. IE mode itself has a defined end-of-life roadmap, and organisations relying on it have been strongly encouraged to migrate.

In short: Microsoft confirmed what the Joomla project had already acted on. The browser was finished.

The enterprise argument — and why it no longer holds

When Joomla 4 launched, the most common pushback came from enterprise environments — government, healthcare, education — where legacy Windows deployments made decommissioning Internet Explorer genuinely difficult. It was a real concern at the time, and worth acknowledging.

In 2026, that argument has run out of road. Microsoft's own retirement of IE 11 in 2022 gave even the most cautious IT departments an unambiguous mandate to move on. Any organisation still citing Internet Explorer as a browser requirement for a public-facing Joomla website is not dealing with a technology problem — it is dealing with a change management problem, and that is not something a CMS framework should be asked to solve.

If you are still encountering internal pressure to maintain IE compatibility, the clearest response is to point to the vendor's own retirement announcement. Microsoft has done the work for you. IE is not a supported browser on any current version of Windows. It is gone.

What this means for Joomla developers in 2026

With Joomla 5 as the current stable release and development continuing toward Joomla 6, the Bootstrap 5 foundation is now well established. Developers building templates and extensions no longer need to carry any mental overhead for IE-era workarounds:

• CSS Grid and Flexbox — Use them freely and fully. No fallbacks required for IE's broken or partial implementations.
• Modern JavaScript — ES6 modules, fetch, async/await, optional chaining — all available without polyfill anxiety.
• CSS custom properties — Variables work as expected across every browser your users will actually be running.
• Web fonts and variable fonts — Render consistently without IE-specific rendering quirks to account for.
• Accessibility improvements — Modern ARIA patterns and focus management work reliably in current browsers in ways IE made difficult.

The removal of IE from scope was not just a housekeeping decision. It was the prerequisite for Joomla's front-end stack to move forward properly. Every modern feature available to Joomla template developers today exists, in part, because that line was drawn clearly and early.

The verdict

Dropping Internet Explorer with Joomla 4 was the right call. It aligned with where the web was heading, it aligned with Bootstrap's own direction, and it was ultimately confirmed by Microsoft's own formal retirement of the browser. The short-term friction for a small number of enterprise environments was real but temporary. The long-term benefit — a cleaner, faster, more capable framework — is permanent.