We’ve just created the stable branch 252 for the IntelliJ IDEA Community 2025.2 release: GitHub - JetBrains/intellij-community at 252
Please consult Incompatible Changes in IntelliJ Platform and Plugins API 2025.* | IntelliJ Platform Plugin SDK and Notable Changes in IntelliJ Platform and Plugins API 2025.* | IntelliJ Platform Plugin SDK for Incompatible as well as Notable API Changes.