PB-427: Release notes 1.3

Updated upgrade library info to include entities info

Author: bdenham

docs/release-notes.md

@@ -22,10 +22,10 @@ The release notes include:
    Page Builder Rows, Banners, and Sliders now have the option to set their heights to the full-height of the page using a number with any CSS unit (px, %, vh, em) or a calculation between units (100vh - 237px). These new features are documented here: [Rows](https://docs.magento.com/m2/ee/user_guide/cms/page-builder-layout-row.html), [Banners](https://docs.magento.com/m2/ee/user_guide/cms/page-builder-media-banner.html), [Sliders](https://docs.magento.com/m2/ee/user_guide/cms/page-builder-media-slider.html).
 
 - {:.new}**Content type upgrade library**<br/>
-   We can now introduce new versions of Page Builder content types without introducing backward-incompatible issues with previous versions. Prior to this release, significant changes to content type configurations would create display and data-loss issues with previously saved Page Builder content types. Our new upgrade library eliminates these issues. We designed the library to upgrade previous versions of content types saved to the database so that they match the configuration changes in the new versions. Page Builder runs the upgrade library on native content types as needed for a new release. This ensures that the built-in Page Builder content types are always upgraded to match any changes we make to content types for a new release. Custom content type developers can also use this upgrade library when making configuration changes to new versions of their custom content types. More information and documentation for upgrading custom content types are provided here: [Upgrading content types](https://devdocs.magento.com/page-builder/docs/how-to/how-to-upgrade-content-types.html){:data-proofer-ignore='true'}.
+   We can now introduce new versions of Page Builder content types without introducing backward-incompatible issues with previous versions. Prior to this release, significant changes to content type configurations would create display and data-loss issues with previously saved Page Builder content types. Our new upgrade library eliminates these issues. We designed the library to upgrade previous versions of content types saved to the database so that they match the configuration changes in the new versions. Page Builder runs the upgrade library on native content types as needed for a new release. This ensures that the built-in Page Builder content types are always upgraded to match any changes we make to content types for a new release.
 
-   {: .bs-callout .bs-callout-info }
-   Unless you are a custom content type developer making configuration changes to your own custom Page Builder content types, there is no need to use the upgrade library. As with Page Builder's native content types, you only need to use the library when you make configuration changes that create display and data-loss issues with your previously saved custom content types.
+   {: .bs-callout .bs-callout-warning }
+   **Please Note:** If you have created additional database entities for storing Page Builder content, you _must_ add those entities to your `etc/di.xml`. If you do not, the Page Builder content stored in your entity will not be updated, causing potential data-loss and display issues. For example, if you have created a blog entity that stores Page Builder content, you must add your blog entity to your `etc/di.xml` file as an `UpgradableEntitiesPool` type so that the upgrade library can update the content in your blog. For more information and instructions on using the upgrade library, see: [How to use the content type upgrade library](https://devdocs.magento.com/page-builder/docs/how-to/how-to-use-upgrade-library.html){:data-proofer-ignore='true'}.
 
 - {:.new}**Documentation on adding new Appearances**<br/>
    Everything you need to know about [adding appearances](https://devdocs.magento.com/page-builder/docs/how-to/how-to-add-appearance.html) for existing or custom content types.

docs_drafts/how-to/how-to-upgrade-content-types.md renamed to docs_drafts/how-to/how-to-use-upgrade-library.md

@@ -1,4 +1,4 @@
-# How to make configuration changes backwards compatible
+# How to use the content type upgrade library
 
 Before version 1.3, changes to a content-type configuration could (and usually would) break the existing content that was saved with the previous configuration. Why? Because a content type's configuration maps data from its source (the master format) to its display templates. So when the configuration mapping changes, the display of existing content might also change. With significant configuration changes, data (such as styles, attributes, and html) is lost. Such changes cause existing content to appear incorrectly, or not at all.