Migration to the new, Region-based Page design

Tridion Sites 9.1 deprecated the old, "flat" Page design in favor of a Region-based Page design. You can choose to continue using the deprecated feature, but because it may be dropped in the next release, we recommend that you migrate to the new functionality as soon as feasible.

In the old Page design, only the Page Template determines the number, type and location of Component Presentations on a published webpage. This makes the Template developer responsible for the layout and type of content on the published webpage.

In the new design, a Page is divided into Regions (which may contain further Regions), each of which can restrict the number and type of Components (or Component Presentations in template-based publishing) within it. This makes the Page editor responsible for the layout and type of content on the published webpage.

A migration of your Pages requires you to go through the following steps:
Region Schema design
Analyze your current Page Templates to find out how they divide the published webpage into physical areas (regions) such as a main content area, a sidebar, a footer and so on, and the types and number of Component Presentations that are allowed in each area.
Use this information to create, for each existing Page Template, a corresponding Page Schema (that is, a Region Schema for the entire Page), with further Regions defined inside it, each with their own Region Schema. As part of defining these Region Schemas, you also specify how many Components (or Component Presentations) are allowed in each Region, which Schema or Schemas they can be based on, and for (template-based publishing) which Component Template or Component Templates they can be rendered with.
Page Template rewrite
Modify each of your current Page Templates so that it no longer performs the logic now encoded in the Region Schemas, such as checking Schemas and Component Templates. Your current Page Templates denote a region with a codeblock like the following, defining which combinations of Schema and Template are allowed in the Region:
<!-- Start Region: {
  title: "My Region",
  allowedComponentTypes: [
    {
      schema: "tcm:2-26-8",
      template: "tcm:2-32-32"
    },
    {
      schema: "tcm:2-27-8",
      template: "tcm:2-32-32"
    }
  ],
  minOccurs: 1,
  maxOccurs: 5
}
-->
Replace this code with the much simpler reference to the Region by its path, for example, for a Region called newsHeadlines found in the top-level Region called sideBar:
<!-- Start Region: {
  title: "sideBar\newsHeadlines"
}
-->
Additionally, modify your Page Templates to gather up Component Presentations from the Page's Regions, rather than directly from the Page itself. Tridion Sites includes a Template Building Block to help you do this.
Training Page editors
When you roll out the new setup in your production environment, explain to your Page editors what this change means for new and existing Pages:
  • When creating a new Page, in the Design tab of the Page dialog, authors should place Components (or Component Presentations) in Regions, which will automatically enforce the restrictions placed on each Region.
  • When modifying an existing Page, in the Design tab of the Page dialog, authors should use the cut-and-paste feature to move Components (or Component Presentations) from the top (Page) level into the Regions where they belong. Depending on how strictly you defined the Page Schema, Page editors may only be able to save the Page after they have moved all Components (or Component Presentations) out of the top level.