Publishing Outlook add-in which uses Outlook preview element - SupportsSharedFolders - outlook-addin

Question

I am developing Outlook add-in which will work with shared mailboxes.
Currently, office add-ins are not available on delegate scenarios but MS has released preview build which supports these scenarios.
https://learn.microsoft.com/en-us/office/dev/add-ins/reference/manifest/supportssharedfolders
My problem is since the manifest.xml has preview elements; I can't upload the it at outlook.office365.com under my add-ins. I get following error.
This app can't be installed. The manifest file doesn't conform to the schema definition. The element 'DesktopFormFactor' in namespace 'http://schemas.microsoft.com/office/mailappversionoverrides/1.1' has invalid child element 'SupportsSharedFolders' in namespace 'http://schemas.microsoft.com/office/mailappversionoverrides/1.1'. List of possible elements expected: 'ExtensionPoint' in namespace 'http://schemas.microsoft.com/office/mailappversionoverrides/1.1'... The element 'DesktopFormFactor' in namespace 'http://schemas.microsoft.com/office/mailappversionoverrides/1.1' has invalid child element 'SupportsSharedFolders' in namespace 'http://schemas.microsoft.com/office/mailappversionoverrides/1.1'. List of possible elements expected: 'ExtensionPoint' in namespace 'http://schemas.microsoft.com/office/mailappversionoverrides/1.1'.
Anyone know any other way to deploy the add-in for users or even test it out without being to upload xml file?
Thanks in advance.
Copy of my manifest.xml file is here.
<?xml version="1.0" encoding="UTF-8"?>
<OfficeApp
xmlns="http://schemas.microsoft.com/office/appforoffice/1.1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:bt="http://schemas.microsoft.com/office/officeappbasictypes/1.0"
xmlns:mailappor="http://schemas.microsoft.com/office/mailappversionoverrides"
xsi:type="MailApp">
<Version>1.0.0.0</Version>
<ProviderName></ProviderName>
<DefaultLocale>en-US</DefaultLocale>
<DisplayName DefaultValue="Sample1" />
<Description DefaultValue="First Sample Angular Add-in"/>
<IconUrl DefaultValue="xxxx.jpg" />
<HighResolutionIconUrl DefaultValue="https://localhost:3000/assets/hi-res-icon.png"/>
<!--If you plan to submit this add-in to the Office Store, uncomment the SupportUrl element below-->
<SupportUrl DefaultValue="https://localhost:3000/support.html" />
<!-- Domains that will be allowed when navigating. For example, if you use ShowTaskpane and then have an href link, navigation will only be allowed if the domain is on this list. -->
<AppDomains>
<AppDomain>AppDomain1</AppDomain>
<AppDomain>AppDomain2</AppDomain>
<AppDomain>AppDomain3</AppDomain>
</AppDomains>
<!--End Basic Settings. -->
<Hosts>
<Host Name="Mailbox" />
</Hosts>
<Requirements>
<Sets>
<Set Name="Mailbox" MinVersion="1.1" />
</Sets>
</Requirements>
<FormSettings>
<Form xsi:type="ItemRead">
<DesktopSettings>
<SourceLocation DefaultValue="https://localhost:3000/index.html"/>
<RequestedHeight>250</RequestedHeight>
</DesktopSettings>
</Form>
</FormSettings>
<Permissions>ReadWriteItem</Permissions>
<Rule xsi:type="RuleCollection" Mode="Or">
<Rule xsi:type="ItemIs" ItemType="Message" FormType="Read" />
</Rule>
<DisableEntityHighlighting>false</DisableEntityHighlighting>
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
<Description resid="residDescription" />
<Requirements>
<bt:Sets DefaultMinVersion="1.3">
<bt:Set Name="Mailbox" />
</bt:Sets>
</Requirements>
<Hosts>
<Host xsi:type="MailHost">
<!-- add information on form factors -->
</Host>
</Hosts>
<Resources>
<!-- add information on resources -->
</Resources>
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides/1.1" xsi:type="VersionOverridesV1_1">
<Requirements>
<bt:Sets DefaultMinVersion="1.3">
<bt:Set Name="Mailbox" />
</bt:Sets>
</Requirements>
<Hosts>
<Host xsi:type="MailHost">
<DesktopFormFactor>
<!-- Location of the Functions that UI-less buttons can trigger (ExecuteFunction Actions). -->
<FunctionFile resid="functionFile" />
<SupportsSharedFolders>true</SupportsSharedFolders>
<!-- Message Read -->
<ExtensionPoint xsi:type="MessageReadCommandSurface">
<!-- Use the default tab of the ExtensionPoint or create your own with <CustomTab id="myTab"> -->
<OfficeTab id="TabDefault">
<!-- Up to 6 Groups added per Tab -->
<Group id="msgReadGroup">
<Label resid="groupLabel" />
<!-- Launch the add-in : task pane button -->
<Control xsi:type="Button" id="msgReadOpenPaneButton">
<Label resid="paneReadButtonLabel" />
<Supertip>
<Title resid="paneReadSuperTipTitle" />
<Description resid="paneReadSuperTipDescription" />
</Supertip>
<Icon>
<bt:Image size="16" resid="icon16" />
<bt:Image size="32" resid="icon32" />
<bt:Image size="80" resid="icon80" />
</Icon>
<Action xsi:type="ShowTaskpane">
<SourceLocation resid="messageReadTaskPaneUrl" />
</Action>
</Control>
<!-- Go to http://aka.ms/ButtonCommands to learn how to add more Controls: ExecuteFunction and Menu -->
</Group>
</OfficeTab>
</ExtensionPoint>
<!-- Go to http://aka.ms/ExtensionPointsCommands to learn how to add more Extension Points: MessageRead, AppointmentOrganizer, AppointmentAttendee -->
</DesktopFormFactor>
</Host>
</Hosts>
<Resources>
<!-- add information on resources -->
</Resources>
</VersionOverrides>
</VersionOverrides>
</OfficeApp>

Answer 1

Explaining #Bubuhubu's answer, and hopefully helping other people out who hit this issue.
If you use the yo generator to initially create your manifest, as is documented in the following Microsoft how to article:
https://learn.microsoft.com/en-us/outlook/add-ins/addin-tutorial
You will notice that the <VersionOverrides> tag is created without a version number. This version of the VersionOverrides element does NOT support the <SupportsSharedFolders> tag, but the 1.1 version DOES.
You might think that you could simply change the xmlns and type tags of the VersionOverrides tag to 1.1 to get the tag supported, but apparently a 1.1 VersionOverrides tag is not supported within an OfficeApp tag. It is however, supported as a child element of a VersionOverrides 1.0 tag.
As a result the simplest way to fix this is to take your manifest.xml from the yo generatort and find:
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
And right after it add:
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides/1.1" xsi:type="VersionOverridesV1_1">
So that it now looks like this:
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides/1.1" xsi:type="VersionOverridesV1_1">
Likewise, near the end-of the document, find:
</VersionOverrides>
and change it to:
</VersionOverrides>
</VersionOverrides>
You can now utilize the <SupportsSharedFolders>, e.g. Your manifest.xml should look something like the following:
. . .
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides/1.1" xsi:type="VersionOverridesV1_1">
<Requirements>
<bt:Sets DefaultMinVersion="1.3">
<bt:Set Name="Mailbox" />
</bt:Sets>
</Requirements>
<Hosts>
<Host xsi:type="MailHost">
<DesktopFormFactor>
<SupportsSharedFolders>true</SupportsSharedFolders>
. . .
</VersionOverrides>
</VersionOverrides>
</OfficeApp>
Hopefully this helps save someone some time.
BTW, apparently when you add a plugin in Outlook it can take up to 60 seconds for it to show up. As a result if you don't see your icon immediately, don't assume at first that it didn't work (Like I originally did).

Answer 2

I've experienced the same issue today. I was able to solve it by moving the
SupportsSharedFolders tag to the beginning of the DesktopFormFactor tag.
Instead of this:
...
<DesktopFormFactor>
<!-- Location of the Functions that UI-less buttons can trigger (ExecuteFunction Actions). -->
<FunctionFile resid="functionFile" />
<SupportsSharedFolders>true</SupportsSharedFolders>
<!-- Message Read -->
...
it should look like this
...
<DesktopFormFactor>
<SupportsSharedFolders>true</SupportsSharedFolders>
<!-- Location of the Functions that UI-less buttons can trigger (ExecuteFunction Actions). -->
<FunctionFile resid="functionFile" />
<!-- Message Read -->
...

Answer 3

Here is sample manifest file which worked for me.
<?xml version="1.0" encoding="UTF-8"?>
<OfficeApp
xmlns="http://schemas.microsoft.com/office/appforoffice/1.1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:bt="http://schemas.microsoft.com/office/officeappbasictypes/1.0"
xmlns:mailappor="http://schemas.microsoft.com/office/mailappversionoverrides"
xsi:type="MailApp">
<!-- Begin Basic Settings: Add-in metadata, used for all versions of Office unless override provided. -->
<!-- IMPORTANT! Id must be unique for your add-in, if you reuse this manifest ensure that you change this id to a new GUID. -->
<Id>XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXX</Id>
<!--Version. Updates from the store only get triggered if there is a version change. -->
<Version>1.0.0.0</Version>
<ProviderName></ProviderName>
<DefaultLocale>en-US</DefaultLocale>
<!-- The display name of your add-in. Used on the store and various places of the Office UI such as the add-ins dialog. -->
<DisplayName DefaultValue="" />
<Description DefaultValue=""/>
<!-- Icon for your add-in. Used on installation screens and the add-ins dialog. -->
<IconUrl DefaultValue="" />
<HighResolutionIconUrl DefaultValue="https://localhost:3000/assets/hi-res-icon.png"/>
<!--If you plan to submit this add-in to the Office Store, uncomment the SupportUrl element below-->
<SupportUrl DefaultValue="https://localhost:3000/support.html" />
<!-- Domains that will be allowed when navigating. For example, if you use ShowTaskpane and then have an href link, navigation will only be allowed if the domain is on this list. -->
<AppDomains>
<AppDomain>AppDomain1</AppDomain>
<AppDomain>AppDomain2</AppDomain>
<AppDomain>AppDomain3</AppDomain>
</AppDomains>
<!--End Basic Settings. -->
<Hosts>
<Host Name="Mailbox" />
</Hosts>
<Requirements>
<Sets>
<Set Name="Mailbox" MinVersion="1.1" />
</Sets>
</Requirements>
<FormSettings>
<Form xsi:type="ItemRead">
<DesktopSettings>
<SourceLocation DefaultValue="https://localhost:3000/index.html"/>
<RequestedHeight>250</RequestedHeight>
</DesktopSettings>
</Form>
</FormSettings>
<Permissions>ReadWriteItem</Permissions>
<Rule xsi:type="RuleCollection" Mode="Or">
<Rule xsi:type="ItemIs" ItemType="Message" FormType="Read" />
</Rule>
<DisableEntityHighlighting>false</DisableEntityHighlighting>
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
<Requirements>
<bt:Sets DefaultMinVersion="1.3">
<bt:Set Name="Mailbox" />
</bt:Sets>
</Requirements>
<Hosts>
<Host xsi:type="MailHost">
<DesktopFormFactor>
<!-- Location of the Functions that UI-less buttons can trigger (ExecuteFunction Actions). -->
<FunctionFile resid="functionFile" />
<!-- Message Read -->
<ExtensionPoint xsi:type="MessageReadCommandSurface">
<!-- Use the default tab of the ExtensionPoint or create your own with <CustomTab id="myTab"> -->
<OfficeTab id="TabDefault">
<!-- Up to 6 Groups added per Tab -->
<Group id="msgReadGroup">
<Label resid="groupLabel" />
<!-- Launch the add-in : task pane button -->
<Control xsi:type="Button" id="msgReadOpenPaneButton">
<Label resid="paneReadButtonLabel" />
<Supertip>
<Title resid="paneReadSuperTipTitle" />
<Description resid="paneReadSuperTipDescription" />
</Supertip>
<Icon>
<bt:Image size="16" resid="icon16" />
<bt:Image size="32" resid="icon32" />
<bt:Image size="80" resid="icon80" />
</Icon>
<Action xsi:type="ShowTaskpane">
<SourceLocation resid="messageReadTaskPaneUrl" />
</Action>
</Control>
<!-- Go to http://aka.ms/ButtonCommands to learn how to add more Controls: ExecuteFunction and Menu -->
</Group>
</OfficeTab>
</ExtensionPoint>
<!-- Go to http://aka.ms/ExtensionPointsCommands to learn how to add more Extension Points: MessageRead, AppointmentOrganizer, AppointmentAttendee -->
</DesktopFormFactor>
</Host>
</Hosts>
<Resources>
<bt:Images>
<bt:Image id="icon16" DefaultValue="https://localhost:3000/assets/XXXX-16.png"/>
<bt:Image id="icon32" DefaultValue="https://localhost:3000/assets/XXXX-32.png"/>
<bt:Image id="icon80" DefaultValue="https://localhost:3000/assets/XXXX-80.png"/>
</bt:Images>
<bt:Urls>
<bt:Url id="functionFile" DefaultValue="https://localhost:3000/function-file/function-file.html"/>
<bt:Url id="messageReadTaskPaneUrl" DefaultValue="https://localhost:3000/index.html"/>
</bt:Urls>
<bt:ShortStrings>
<bt:String id="groupLabel" DefaultValue="My Add-in Group"/>
<bt:String id="customTabLabel" DefaultValue="My Add-in Tab"/>
<bt:String id="paneReadButtonLabel" DefaultValue="Display all properties"/>
<bt:String id="paneReadSuperTipTitle" DefaultValue="Get all properties"/>
</bt:ShortStrings>
<bt:LongStrings>
<bt:String id="paneReadSuperTipDescription" DefaultValue="Opens a pane displaying all available properties. This is an example of a button that opens a task pane."/>
</bt:LongStrings>
</Resources>
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides/1.1" xsi:type="VersionOverridesV1_1">
<Requirements>
<bt:Sets DefaultMinVersion="1.3">
<bt:Set Name="Mailbox" />
</bt:Sets>
</Requirements>
<Hosts>
<Host xsi:type="MailHost">
<DesktopFormFactor>
<SupportsSharedFolders>true</SupportsSharedFolders>
<!-- Location of the Functions that UI-less buttons can trigger (ExecuteFunction Actions). -->
<FunctionFile resid="functionFile" />
<!-- Message Read -->
<ExtensionPoint xsi:type="MessageReadCommandSurface">
<!-- Use the default tab of the ExtensionPoint or create your own with <CustomTab id="myTab"> -->
<OfficeTab id="TabDefault">
<!-- Up to 6 Groups added per Tab -->
<Group id="msgReadGroup">
<Label resid="groupLabel" />
<!-- Launch the add-in : task pane button -->
<Control xsi:type="Button" id="msgReadOpenPaneButton">
<Label resid="paneReadButtonLabel" />
<Supertip>
<Title resid="paneReadSuperTipTitle" />
<Description resid="paneReadSuperTipDescription" />
</Supertip>
<Icon>
<bt:Image size="16" resid="icon16" />
<bt:Image size="32" resid="icon32" />
<bt:Image size="80" resid="icon80" />
</Icon>
<Action xsi:type="ShowTaskpane">
<SourceLocation resid="messageReadTaskPaneUrl" />
</Action>
</Control>
<!-- Go to http://aka.ms/ButtonCommands to learn how to add more Controls: ExecuteFunction and Menu -->
</Group>
</OfficeTab>
</ExtensionPoint>
<!-- Go to http://aka.ms/ExtensionPointsCommands to learn how to add more Extension Points: MessageRead, AppointmentOrganizer, AppointmentAttendee -->
</DesktopFormFactor>
</Host>
</Hosts>
<Resources>
<bt:Images>
<bt:Image id="icon16" DefaultValue="https://localhost:3000/assets/XXXX-16.png"/>
<bt:Image id="icon32" DefaultValue="https://localhost:3000/assets/XXXXX-32.png"/>
<bt:Image id="icon80" DefaultValue="https://localhost:3000/assets/XXXX-80.png"/>
</bt:Images>
<bt:Urls>
<bt:Url id="functionFile" DefaultValue="https://localhost:3000/function-file/function-file.html"/>
<bt:Url id="messageReadTaskPaneUrl" DefaultValue="https://localhost:3000/index.html"/>
</bt:Urls>
<bt:ShortStrings>
<bt:String id="groupLabel" DefaultValue="My Add-in Group"/>
<bt:String id="customTabLabel" DefaultValue="My Add-in Tab"/>
<bt:String id="paneReadButtonLabel" DefaultValue="Display all properties"/>
<bt:String id="paneReadSuperTipTitle" DefaultValue="Get all properties"/>
</bt:ShortStrings>
<bt:LongStrings>
<bt:String id="paneReadSuperTipDescription" DefaultValue="Opens a pane displaying all available properties. This is an example of a button that opens a task pane."/>
</bt:LongStrings>
</Resources>
</VersionOverrides>
</VersionOverrides>
</OfficeApp>