Publish Extensions to Managed Packages

An extension is any package, component, or set of components that adds to the functionality of a managed package. An extension requires that the base managed package is installed in the org. For example, if you have built a recruiting app, an extension to this app can include a component for performing background checks on candidates.

Available in: Group, Professional, Enterprise, Performance, Unlimited, and Developer Editions

User Permissions Needed
To create packages:	Create AppExchange Packages
To upload packages:	Upload AppExchange Packages

Building a new app? Have you considered using second-generation managed packages? Flexible versioning and the ability to share a namespace across packages are just two reasons why developers love creating second-generation managed packages. We think you’d love it, too. To learn more, see: Why Switch to Second-Generation Managed Packages, and Comparison of First- and Second-Generation Managed Packages.

Note

The community of developers, users, and visionaries building and publishing apps on AppExchange is part of what makes Salesforce Platform such a rich development platform. Use this community to build extensions to other apps and encourage them to build extensions to your apps.

When working with both first-generation (1GP) and second-generation (2GP) managed packages, only certain combinations of packages are supported.

Can I extend a first-generation managed package with a second-generation managed package?	Yes A second-generation managed package can depend on a first-generation managed package.
Can I extend a second-generation managed package with another second-generation managed package?	Yes
Can I extend a second-generation managed package with a first-generation managed package?	No A first-generation managed package can’t depend on a second-generation managed package, and we block the installation of managed 2GP packages in managed 1GP packaging orgs. We can override this behavior on an individual basis. To share your scenario and request an override, log a case with Salesforce Partner Support. We’re investigating how to support this dependency scenario more broadly.
Can I extend a first-generation managed package with another first-generation managed package?	Yes

To publish extensions to a managed package:

Install the base package in the Salesforce org that you plan to use to upload the extension.
Build your extension components.
To build an extension, install the base package and include a dependency to that base package in your package. The extension attribute automatically becomes active.
Note
Create a package and add your extension components. Salesforce automatically includes some related components.
Upload the new package that contains the extension components.
Proceed with the publishing process as usual. For information on creating a test drive or registering and publishing your app, go to Salesforce Partner Community.

Packages can’t be upgraded to Managed - Beta if they’re used within the same org as an extension.

Note

First-Generation Managed Packaging Developer Guide

Publish Extensions to Managed Packages