Switching from Admin Classic to Pimcore Studio – Before the Window Closes.
The classic ExtJS admin interface doesn't fade out gradually, it disappears on a fixed date. Planning the switch to Pimcore Studio now means using the last window in which both interfaces run side by side.
Pimcore Studio (the two Studio bundles for UI and backend, reachable through a dedicated Studio interface) replaces the classic ExtJS admin interface. That's not a new color scheme for the same application, it's an architecture shift: new frontend framework, new plugin architecture, hard new infrastructure dependencies. Anyone treating this as a plain UI update is systematically underestimating the effort.
The Dual-UI Window: How Long Classic and Studio Run Side by Side
Platform Version 2025.4 (Pimcore 12.3, LTS through December 2028) is the last version in which the classic admin UI and Studio run side by side. A gradual switch at your own pace is possible within this window. Studio was pre-GA during the 2025.x line; general availability (GA) arrived with Platform Version 2026.1.
What Disappears Completely With Platform 2026.1
Starting with Platform Version 2026.1, the classic admin UI is fully removed: all ExtJS code, tag editors, class-definition editors, and admin panels. The classic admin UI bundle (version 2.x) doesn't get a 2026-compatible release. On top of that, further bundles disappear or get reduced with 2026.1: GlossaryBundle, SimpleBackendSearchBundle (absorbed into Studio/Generic Data Index), StaticRouteBundle, WordExportBundle, XliffBundle, along with individual features like perspective-editor, file-explorer, and system-info. The SeoBundle stays, but reduced to redirects and sitemaps. Each of these removals should be checked against actual usage in your own system before planning the hop to 2026.1.
The Technical Prerequisites for Studio
Studio depends hard on the Generic Data Index and therefore on OpenSearch or Elasticsearch: without a running search cluster, there's no functional admin interface. On top of that come a Mercure hub, the Generic Execution Engine, and dedicated firewall configuration. The skeleton for Platform Version 2026.1 already ships these components in its Compose stack: OpenSearch, Mercure, RabbitMQ, Redis, and Supervisord. Anyone who doesn't build this infrastructure ahead of time simply can't run Studio in production, regardless of the state of the rest of the migration.
ExtJS Plugins Are Rewrites, Not Ports
The point that gets underestimated in many plans: ExtJS extensions (AdminEvents, ExtJS plugins, admin controllers) don't carry over to Studio automatically. Studio brings a new React/TypeScript plugin SDK that requires genuine rewrites, not migration scripts for existing ExtJS code. Any ExtJS customization still being newly built on 12.3 today is a full write-off at the hop to 2026.1.
Praetorian Angle: The Roadmap Inside the Dual Window
We plan the Studio switch within the window that Platform 2025.4 provides, rather than starting only once 2026.1 ships: a Studio pilot on part of the system, a complete inventory of all ExtJS extensions, a prioritized rewrite roadmap, and the infrastructure build-out for OpenSearch and Mercure before they become a prerequisite for production operation, often alongside migrating Pimcore 11 to 12 as part of our Pimcore Migration work.
Warning: What Gets Built in ExtJS Today Is a Write-Off Tomorrow
If a project is currently running on Platform 2025.4 and needs a new admin extension, the obvious temptation is to build it quickly in ExtJS because the team already knows it. The result is an investment with a built-in expiration date: every new ExtJS customization has to be rebuilt as a rewrite on the new plugin SDK at the hop to 2026.1. Where possible, as part of our Custom Development work we therefore plan new backend extensions against Studio's architecture already, even while the project is still running on the classic UI today.
Why the Dual Window Is Shorter Than It Looks
On paper, "Platform 2025.4 runs through December 2028" sounds like plenty of time. For the Studio switch, though, a different date matters: the release of Platform 2026.1, at which point the classic UI disappears entirely, regardless of the predecessor version's LTS end date. Anyone who only reacts once 2026.1 is already available has already missed the real window for an orderly, phased switch and faces a forced big-bang change plus a full ExtJS rewrite under time pressure. That's exactly what we try to avoid with an early inventory.
Frequently Asked Questions
When does the classic Pimcore admin interface disappear for good?
With Platform Version 2026.1. Platform Version 2025.4 is the last version in which the classic UI and Studio run side by side.
What happens to my existing ExtJS extensions during the switch?
They don't carry over automatically. Studio brings a new React/TypeScript plugin SDK, and every ExtJS extension has to be rebuilt on it.
Do I absolutely need OpenSearch or Elasticsearch for Pimcore Studio?
Yes. Studio depends hard on the Generic Data Index, which doesn't function without one of these search clusters: without it, there's no functional admin interface as of Platform 2026.1.
Should I still invest in ExtJS customizations right now?
Only if the short-term benefit outweighs the full write-off at the 2026.1 hop. In most cases, it's more sensible to plan new extensions against Studio's architecture already.
How much time do I have to plan the switch to Studio?
Until Platform Version 2026.1 ships, which removes the classic UI. Platform 2025.4 itself runs with LTS support through December 2028, but without the classic admin UI starting with 2026.1.
What does a switch to Pimcore Studio cost?
That depends on the scope of existing ExtJS extensions and the necessary infrastructure build-out. An extension inventory as part of an audit surfaces this scope up front.
Is Pimcore Studio already production-ready?
Studio reached general availability (GA) with Platform Version 2026.1, after a pre-GA phase during the 2025.x line. The concrete maturity level for your use case is best assessed in a pilot project.
Use the dual window now?
We inventory ExtJS extensions and plan the Studio switch at your own pace.
Get Your Studio Switch Planned