JetBrains will stop maintaining Kotlin Notebook as a product: from IntelliJ IDEA 2026.2 it is unbundled and gets no new features, and no compatible plugin will be published for 2026.3 and beyond; the source moves to open source

Kotlin Notebook is the interactive, cell-based environment JetBrains bundled into IntelliJ IDEA for people who wanted to poke at Kotlin the way data scientists poke at Python — run a snippet, see the result inline, iterate, chart a dataframe without leaving the IDE. JetBrains has now announced it is sunsetting it as a product and will no longer maintain it.

This is a soft sunset defined by IDE version rather than a date on a calendar. Through v2026.1, Kotlin Notebook remains bundled with IntelliJ IDEA exactly as it is today. In v2026.2, it is unbundled from the IDE and JetBrains stops developing new features for it — though the plugin stays installable from the marketplace and is compatible with that release. From v2026.3 and beyond, JetBrains will not publish a compatible plugin at all. Nothing you have built stops working the day you read this, and there is no forced migration on a deadline; what changes is that the tool moves from “maintained by JetBrains” to “frozen,” and eventually to “not shipped by JetBrains for your IDE version.”

Because JetBrains anchored the change to versions rather than to a specific day, this entry carries no countdown — inventing a date from a release cadence would be a guess. What is definite is the direction: new feature work on Kotlin Notebook has stopped, so any workflow that leans on it is now building on a product with a fixed shelf life tied to how long you stay on 2026.2 or earlier.

There are two off-ramps, and they suit different needs. JetBrains’ own recommendation is Kotlin DataFrame: with its compiler plugin, the schema-aware APIs and generated column accessors that used to justify reaching for a notebook now work directly inside ordinary Gradle and Maven projects, which covers a lot of the data-wrangling use case without a notebook at all. For genuine notebook-style, cell-by-cell exploration, the plugin itself is not disappearing — JetBrains says it will publish the source on GitHub under the Apache License 2.0 so the community can keep it alive, and there is always Jupyter with a Kotlin kernel as a vendor-independent option. The useful thing to do with this runway is decide which of those you want before you upgrade to 2026.3, rather than discovering at upgrade time that the bundled tool you relied on is simply not there.