diff --git a/versions/2016-10-31.md b/versions/2016-10-31.md
index 241ed54638..172922cfc6 100644
--- a/versions/2016-10-31.md
+++ b/versions/2016-10-31.md
@@ -1239,7 +1239,7 @@ Enable custom domains to be configured with your Api. Currently only supports Cr
 ```yaml
 Domain:
   DomainName: String # REQUIRED | custom domain name being configured on the api, "www.example.com"
-  CertificateARN: String # REQUIRED | Must be a valid [certificate ARN](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-certificatemanager-certificate.html), and for EDGE endpoint configuration the certificate must be in us-east-1
+  CertificateArn: String # REQUIRED | Must be a valid [certificate ARN](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-certificatemanager-certificate.html), and for EDGE endpoint configuration the certificate must be in us-east-1
   EndpointConfiguration: "EDGE" # optional | Default value is REGIONAL | Accepted values are EDGE | REGIONAL
   BasePath:
     - String # optional | Default value is '/' | List of basepaths to be configured with the ApiGateway Domain Name