New feature: Customize apps in Microsoft Teams | But can the Microsoft apps also be customized?

One of my clients uses the Community's app in Teams (Yammer) but isn't so fond of its name and icon.  With this new feature you can customize apps in Teams:

https://docs.microsoft.com/nl-nl/MicrosoftTeams/customize-apps

Very nice! But can anybody tell me if Microsoft apps like Community's/Yammer will support customizing?