Migrating LSP4IJ to use JetBrains-provided LSP4J (2025.2+)

[angelozerr]

Migrating LSP4IJ to use JetBrains-provided LSP4J (2025.2+)

Hi everyone,

Since 2025.2, JetBrains provides LSP4J directly within the platform, which unifies the ecosystem and is becoming the official reference. This has important implications for LSP4IJ, as continuing to include our own LSP4J libraries will increasingly cause linkage issues (see issue #459).

I’m considering removing the LSP4J libraries from the LSP4IJ project (see corresponding PR), which would mean LSP4IJ relies on the version of LSP4J provided by JetBrains.

⚠️ This implies:

• Mandatory migration for all users to IntelliJ 2025.2 or later.
• Potential need to handle compatibility for older versions if some users can’t upgrade immediately.

Proposed roadmap

1. Release 0.19.0: release with the current setup, so migration is not forced immediately.
2. Release 0.20.0: remove the bundled LSP4J libraries and migrate to the JetBrains-provided ones.

Questions for the community

• Would this migration to the JetBrains-provided LSP4J be inconvenient for any of you?

Your feedback is welcome to help determine the best path forward for this change.

Thanks in advance!

cc @CppCXY @InSyncWithFoo @seachicken @KUGDev @AlexWeinstein92 @aparnamichael @MituuZ @turkeylurkey @mrglavas @koxudaxi @FalsePattern @onriv @kristofvb @kdvolder @rcjsuen @jansorg @SCWells72 @ericdallo @nikunjarora12345 @DetachHead @sergeysavchuk @bzoracler @bratorange @tim-sh