Requirements element

Article
08/05/2024

The meaning of this element depends on whether it's used in the base manifest, as a child of a <VersionOverrides> element, or as a child of the Override element.

Tip

Before using this element, be familiar with Specify Office hosts and API requirements

In the base manifest

When used in the base manifest (that is, as a direct child of OfficeApp), the <Requirements> element specifies the minimum set of Office JavaScript API requirements (requirement sets and/or methods) that your Office Add-in needs to be activated by Office. The add-in will not be activated on any combination of Office version and platform (such as Windows, Mac, web, and iOS or iPad) that doesn't support the specified methods and requirement sets.

Add-in type: Task pane, Mail

As a child of a VersionOverrides element

When used as a child of VersionOverrides, specifies the minimum set of Office JavaScript API requirements (requirement sets and/or methods) that must be supported by the Office version and platform (such as Windows, Mac, web, and iOS or iPad) in order for the settings in the <VersionOverrides> element that override base manifest settings to take effect.

Consider an add-in that specifies requirement A in the base manifest and specifies requirement B inside the <VersionOverrides>.

If the platform and Office version don't support A, then the add-in isn't activated and Office doesn't parse the <VersionOverrides> section of the manifest.
If both A and B are supported, then the add-in is activated and all the markup in the <VersionOverrides> takes effect.
If A is supported, but B is not, then the add-in is activated and some of the markup in the <VersionOverrides> takes effect. Specifically, child elements of the <VersionOverrides> that don't override base manifest elements take effect. For example, a <WebApplicationInfo> element or a <EquivalentAddins> take effect. However, all child elements of the <VersionOverrides> that override a base manifest element, such as <Hosts>, don't take effect. Instead, Office uses the values of the base manifest markup that would otherwise have been overridden.

Add-in type: Task pane, Mail

Valid only in these VersionOverrides schemas:

Task pane 1.0
Mail 1.0
Mail 1.1

For more information, see Version overrides in the add-in only manifest.

Associated with these requirement sets:

AddinCommands 1.1 when the parent <VersionOverrides> is type Taskpane 1.0.
Mailbox 1.3 when the parent <VersionOverrides> is type Mail 1.0.
Mailbox 1.5 when the parent <VersionOverrides> is type Mail 1.1.

Remarks

The <Requirements> element serves no purpose in a <VersionOverrides> if it specifies no additional requirements that aren't specified in a <Requirements> in the base manifest. If the Office version and platform don't support the requirements in the base manifest, the add-in isn't activated and the <VersionOverrides> element isn't parsed. For this reason, you should use a <Requirements> element in a <VersionOverrides> only when both of these conditions are met:

Your add-in has extra features that are implemented with configuration in a <VersionOverrides> (such as Add-in Commands), and that require a method or requirement set that is not specified in a <Requirements> element in the base manifest.
Your add-in is useful and should be activated (but without the extra features), even in a combination of platform and Office version that doesn't support the requirements needed for the extra features.

Tip

Do not repeat Requirement elements from the base manifest inside a <VersionOverrides>. Doing so has no effect and is potentially misleading as to the purpose of the <Requirements> element inside a <VersionOverrides>.

Warning

Use great care before using a <Requirements> element in a <VersionOverrides>, because on platform and version combinations that don't support the requirement, none of the add-in commands will be installed, even those that invoke functionality that doesn't need the requirement. Consider, for example, an add-in that has two custom ribbon buttons. One of them calls Office JavaScript APIs that are available in requirement set ExcelApi 1.4 (and later). The other calls APIs that are only available in ExcelApi 1.9 (and later). If you put a requirement for ExcelApi 1.9 in the <VersionOverrides>, then when 1.9 is not supported neither button will appear on the ribbon. A better strategy in this scenario would be to use the technique described in Runtime checks for method and requirement set support. The code invoked by the second button first uses isSetSupported to check for support of ExcelApi 1.9. If it isn't supported, the code gives the user a message saying that this feature of the add-in isn't available on their version of Office.

Note

In Mail add-ins, it's possible for a <VersionOverrides> 1.1 to be nested inside a <VersionOverrides> 1.0. Office will always use the highest version <VersionOverrides> that is supported by the platform and Office version.

As a child of the Override element

A <Requirements> element can be a child of an Override element in the context of an ancestor ExtendedOverrides element. An <Override> element expresses a conditional and can be read as an "If ... then ..." statement. If the <Override> element is of type RequirementTokenOverride (meaning that the xsi:type of its parent Token element is RequirementsToken), then the child <Requirements> element expresses the condition, and the Value attribute is the consequent. For example, the first <Override> in the following is read "If the current platform supports FeatureOne version 1.7, then use string 'oldAddinVersion' in place of the ${token.requirements} token in the URL of the grandparent <ExtendedOverrides> (instead of the default string 'upgrade')." For more information, see ExtendedOverrides.

<ExtendedOverrides Url="http://contoso.com/addinmetadata/${token.requirements}/extended-manifest-overrides.json">
    <Tokens>
        <Token Name="requirements" DefaultValue="upgrade" xsi:type="RequirementsToken">
            <Override Value="oldAddinVersion">
                <Requirements>
                    <Sets>
                        <Set Name="FeatureOne" MinVersion="1.7" />
                    </Sets>
                </Requirements>
            </Override>
            <Override Value="currentAddinVersion">
                <Requirements>
                    <Sets>
                        <Set Name="FeatureOne" MinVersion="1.8" />
                    </Sets>
                    <Methods>
                        <Method Name="MethodThree" />
                    </Methods>
                </Requirements>
            </Override>
        </Token>
    </Tokens>
</ExtendedOverrides>

Add-in type: Task pane

Syntax

<Requirements>
   ...
</Requirements>

Contained in

Can contain

The <Requirements> element can contain the following child elements depending on the add-in type.

Element	Content	Mail	TaskPane
Sets	Yes	Yes	Yes
Methods	Yes	No	Yes

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