Cannot update Java and Kotlin by IntelliJ IDEA in Cursor: requested version was not found

Problem

Updating the Java and Kotlin by IntelliJ IDEA extension in Cursor from an earlier version, for example 0.0.13, fails with:

Error while installing 'Java and Kotlin by IntelliJ IDEA' extension.

The developer console (Help | Toggle Developer Tools, Console tab) shows:

ERR NotFound: The extension 'jetbrains.intellij-server' cannot be installed because the requested version '1.0.27' was not found.

Install Specific Version fails in the same way while an earlier version is installed. The Update to button can list only the installed version, or no update button appears. The problem occurs on macOS and Windows. A fresh install, with no earlier version present, succeeds.

Cause

Cursor reads extensions from its own mirror of the Open VSX Registry. Right after a new extension release, that mirror can lag behind Open VSX. The version list that Cursor shows and the version that it can download then do not match. The update request fails with NotFound.

Visual Studio Code installs the extension from the Visual Studio Marketplace and is not affected.

Resolution

The update starts to work without any action after the Cursor mirror syncs with Open VSX. To update immediately, use one of the options below.

Option 1. Reinstall the extension

1. Open the Extensions view with Ctrl+Shift+X (Windows, Linux) or Cmd+Shift+X (macOS).
2. Find Java and Kotlin by IntelliJ IDEA and click Uninstall.
3. Reload the Cursor window when prompted.
4. Search for the extension again and click Install.

Option 2. Install the VSIX file manually

1. Open the Open VSX page of the extension.
2. Download the VSIX file that matches the operating system and CPU architecture.
3. In Cursor, open the Command Palette with Ctrl+Shift+P (Windows, Linux) or Cmd+Shift+P (macOS).
4. Run Extensions: Install from VSIX... and select the downloaded file.
5. Reload the Cursor window when prompted.