diff --git a/versions/3.1.0.md b/versions/3.1.0.md
index f0c7f54abe..a5ccaea596 100644
--- a/versions/3.1.0.md
+++ b/versions/3.1.0.md
@@ -3165,12 +3165,12 @@ animals:
 #### <a name="securitySchemeObject"></a>Security Scheme Object
 
 Defines a security scheme that can be used by the operations.
-Supported schemes are HTTP authentication, an API key (either as a header, a cookie parameter or as a query parameter), OAuth2's common flows (implicit, password, application and access code) as defined in [RFC6749](https://tools.ietf.org/html/rfc6749), and [OpenID Connect Discovery](https://tools.ietf.org/html/draft-ietf-oauth-discovery-06).
+Supported schemes are HTTP authentication, an API key (either as a header, a cookie parameter or as a query parameter), mutual TLS (use of a client certificate), OAuth2's common flows (implicit, password, application and access code) as defined in [RFC6749](https://tools.ietf.org/html/rfc6749), and [OpenID Connect Discovery](https://tools.ietf.org/html/draft-ietf-oauth-discovery-06).
 
 ##### Fixed Fields
 Field Name | Type | Applies To | Description
 ---|:---:|---|---
-<a name="securitySchemeType"></a>type | `string` | Any | **REQUIRED**. The type of the security scheme. Valid values are `"apiKey"`, `"http"`, `"oauth2"`, `"openIdConnect"`.
+<a name="securitySchemeType"></a>type | `string` | Any | **REQUIRED**. The type of the security scheme. Valid values are `"apiKey"`, `"http"`, `"mutualTLS"`, `"oauth2"`, `"openIdConnect"`.
 <a name="securitySchemeDescription"></a>description | `string` | Any | A short description for security scheme. [CommonMark syntax](http://spec.commonmark.org/) MAY be used for rich text representation.
 <a name="securitySchemeName"></a>name | `string` | `apiKey` | **REQUIRED**. The name of the header, query or cookie parameter to be used.
 <a name="securitySchemeIn"></a>in | `string` | `apiKey` | **REQUIRED**. The location of the API key. Valid values are `"query"`, `"header"` or `"cookie"`.