diff --git a/types/sinon/index.d.ts b/types/sinon/index.d.ts
index 53c9ec28c04d67..9eb93d6d94b7ed 100644
--- a/types/sinon/index.d.ts
+++ b/types/sinon/index.d.ts
@@ -793,15 +793,9 @@ declare namespace Sinon {
 
     interface SinonAssert {
         // Properties
-        /**
-         * Defaults to AssertError.
-         */
-        failException: string;
         /**
          * Every assertion fails by calling this method.
-         * By default it throws an error of type sinon.assert.failException.
-         * If the test framework looks for assertion errors by checking for a specific exception, you can simply override the kind of exception thrown.
-         * If that does not fit with your testing framework of choice, override the fail method to do the right thing.
+         * If your testing framework of choice looks for assertion errors by checking for a specific exception, you can override the `fail` method to do the right thing.
          */
         fail(message?: string): void; // Overridable
         /**
diff --git a/types/sinon/package.json b/types/sinon/package.json
index edfacc955f5444..8a96e48933b9ed 100644
--- a/types/sinon/package.json
+++ b/types/sinon/package.json
@@ -1,7 +1,7 @@
 {
     "private": true,
     "name": "@types/sinon",
-    "version": "20.0.9999",
+    "version": "21.0.9999",
     "projects": [
         "https://sinonjs.org"
     ],