Updates per Issue #4653

Author: chrisda

exchange/exchange-ps/exchange/antispam-antimalware/New-DkimSigningConfig.md

@@ -23,8 +23,12 @@ For information about the parameter sets in the Syntax section below, see [Excha
 
 ```
 New-DkimSigningConfig [-DomainName] <SmtpDomainWithSubdomains> [-Enabled] <Boolean>
- [-AdminDisplayName <String>] [-BodyCanonicalization <CanonicalizationType>] [-Confirm]
- [-HeaderCanonicalization <CanonicalizationType>] [-KeySize <UInt16>] [-WhatIf] [<CommonParameters>]
+ [-AdminDisplayName <String>]
+ [-BodyCanonicalization <CanonicalizationType>]
+ [-Confirm]
+ [-HeaderCanonicalization <CanonicalizationType>]
+ [-KeySize <UInt16>]
+ [-WhatIf] [<CommonParameters>]
 ```
 
 ## DESCRIPTION
@@ -160,7 +164,9 @@ Accept wildcard characters: False
 ```
 
 ### -KeySize
-The KeySize parameter specifies the size in bits of the public key that's used in the DKIM signing policy. The only available value is 1024.
+The KeySize parameter specifies the size in bits of the public key that's used in the DKIM signing policy. Valid values are 1024 or 2048.
+
+RSA keys are supported; Ed25519 keys aren't supported.
 
 ```yaml
 Type: UInt16

exchange/exchange-ps/exchange/antispam-antimalware/Rotate-DkimSigningConfig.md

@@ -83,7 +83,9 @@ Accept wildcard characters: False
 ```
 
 ### -KeySize
-The KeySize parameter specifies the size in bits of the public key that's used in the DKIM signing policy. The available values are 1024 and 2048.
+The KeySize parameter specifies the size in bits of the public key that's used in the DKIM signing policy.  Valid values are 1024 or 2048.
+
+RSA keys are supported; Ed25519 keys aren't supported.
 
 ```yaml
 Type: UInt16