[Home](./index.md) > [sip.js](./sip.js.md) > [SIPExtension](./sip.js.sipextension.md) ## SIPExtension enum SIP extension support level. Signature: ```typescript export declare enum SIPExtension ``` ## Enumeration Members | Member | Value | Description | | --- | --- | --- | | Required | "Required" | | | Supported | "Supported" | | | Unsupported | "Unsupported" | |