2.3.9.4 release notes
2.3.9.4 Issue 2907 - Spring '26 / API v66.0 update Updated the SOAP client for API v66.0. Updated the API version used for primary communication with Salesforce APIs to 66.0. Added 66.0 as an available API version number for configured connections. Updated metadata.xsd based on the API v66.0 Metadata API SOAP WSDL. Updated the OST version number to prompt regeneration for system API changes in Spring '26. Updated the bundled completions?type=apex Tooling REST API response to be based on the API v66.0 REST endpoint. Updated Visualforce, Aura, and LWC components, functions, modules, etc., for Spring '26 changes. Note that I have not yet reconciled IC's own LWC TypeScript definitions with the latest from @salesforce/lightning-types but I do plan to do that shortly. If you're running into issues with some incompatibility between the two, please let me know about the specific instance(s) and I'll fast-track those. Updated the bundled SLDS CSS and SVG...