diff --git a/packages/mermaid/src/config.type.ts b/packages/mermaid/src/config.type.ts
index 335e33b19..9be24e030 100644
--- a/packages/mermaid/src/config.type.ts
+++ b/packages/mermaid/src/config.type.ts
@@ -122,14 +122,6 @@ export interface MermaidConfig {
    *
    */
   secure?: string[];
-  /**
-   * This option specifies if Mermaid can expect the dependent to include KaTeX stylesheets for browsers
-   * without their own MathML implementation. If this option is disabled and MathML is not supported, the math
-   * equations are replaced with a warning. If this option is enabled and MathML is not supported, Mermaid will
-   * fall back to legacy rendering for KaTeX.
-   *
-   */
-  legacyMathML?: boolean;
   /**
    * This option controls if the generated ids of nodes in the SVG are
    * generated randomly or based on a seed.