diff --git a/packages/mermaid/src/config.type.ts b/packages/mermaid/src/config.type.ts
index 9be24e030..f7ff8b272 100644
--- a/packages/mermaid/src/config.type.ts
+++ b/packages/mermaid/src/config.type.ts
@@ -122,6 +122,13 @@ 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.