Merge pull request #91029 from MichaelFrandsenMVP/patch-1

Updated requirement info around PFX files

Author: Jak-MS

articles/app-service/configure-ssl-certificate.md

@@ -282,6 +282,11 @@ If your certificate authority gives you multiple certificates in the certificate
 
 Now, export your merged TLS/SSL certificate with the private key that was used to generate your certificate request. If you generated your certificate request using OpenSSL, then you created a private key file.
 
+> [!NOTE]
+> OpenSSL v3 creates certificate serials with 20 octets (40 chars) as the X.509 specification allows. Currently only 10 octets (20 chars) is supported when uploading certificate PFX files.
+> OpenSSL v3 also changed default cipher from 3DES to AES256, but this can be overridden on the command line.
+> OpenSSL v1 uses 3DES as default and only uses 8 octets (16 chars) in the serial, so the PFX files generated are supported without any special modifications.
+
 1. To export your certificate to a PFX file, run the following command, but replace the placeholders _<private-key-file>_ and _<merged-certificate-file>_ with the paths to your private key and your merged certificate file.
 
    ```bash