Namespace: http://schemas.microsoft.com/exchange/services/2006/messages

The InstallAppType complex type specifies a request to install a mail add-in. This type extends the BaseRequestType complex type, as specified in [MS-OXWSCDATA] section

 <xs:complexType name="InstallAppType" xmlns:xs="http://www.w3.org/2001/XMLSchema">
   <xs:complexContent mixed="false">
     <xs:extension base="tns:BaseRequestType">
         <xs:element minOccurs="1" maxOccurs="1" name="Manifest" type="xs:base64Binary"/>
         <xs:element minOccurs="0" maxOccurs="1" name="MarketplaceAssetId" type="xs:string"/>
         <xs:element minOccurs="0" maxOccurs="1" name="MarketplaceContentMarket" type="xs:string"/>
         <xs:element minOccurs="0" maxOccurs="1" name="SendWelcomeEmail" type="xs:boolean"/>

Manifest: An element of type base64Binary, as defined in [XMLSCHEMA2/2], that contains the mail add-in manifest file encoded with base64 encoding.

MarketplaceAssetId: An element of type string, as defined in [XMLSCHEMA2/2], that specifies the asset id of the add-in. <3>

MarketplaceContentMarket: An element of type string that specifies the target market for content.<4>

SendWelcomeEmail: An element of type boolean, as defined in [XMLSCHEMA2/2], that specifies whether to send a welcome email for the add-in. <5>