diff --git a/README.md b/README.md
index d8376a3..68bcf63 100644
--- a/README.md
+++ b/README.md
@@ -55,7 +55,7 @@ However, the amount of effort needed to maintain and develop new features and pr
 
 Make sure all dependencies have been installed before moving on:
 
-- [WordPress](https://wordpress.org/) >= 5.4
+- [WordPress](https://wordpress.org/) >= 5.9
 - [PHP](https://secure.php.net/manual/en/install.php) >= 7.4.0 (with [`php-mbstring`](https://secure.php.net/manual/en/book.mbstring.php) enabled)
 - [Composer](https://getcomposer.org/download/)
 - [Node.js](http://nodejs.org/) >= 16
diff --git a/app/setup.php b/app/setup.php
index 9b6d0ea..5469bb9 100644
--- a/app/setup.php
+++ b/app/setup.php
@@ -58,60 +58,6 @@ add_action('after_setup_theme', function () {
         'primary_navigation' => __('Primary Navigation', 'sage')
     ]);
 
-    /**
-     * Register the editor color palette.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#block-color-palettes
-     */
-    add_theme_support('editor-color-palette', []);
-
-    /**
-     * Register the editor color gradient presets.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#block-gradient-presets
-     */
-    add_theme_support('editor-gradient-presets', []);
-
-    /**
-     * Register the editor font sizes.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#block-font-sizes
-     */
-    add_theme_support('editor-font-sizes', []);
-
-    /**
-     * Register relative length units in the editor.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#support-custom-units
-     */
-    add_theme_support('custom-units');
-
-    /**
-     * Enable support for custom line heights in the editor.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#supporting-custom-line-heights
-     */
-    add_theme_support('custom-line-height');
-
-    /**
-     * Enable support for custom block spacing control in the editor.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#spacing-control
-     */
-    add_theme_support('custom-spacing');
-
-    /**
-     * Disable custom colors in the editor.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#disabling-custom-colors-in-block-color-palettes
-     */
-    add_theme_support('disable-custom-colors');
-
-    /**
-     * Disable custom color gradients in the editor.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#disabling-custom-gradients
-     */
-    add_theme_support('disable-custom-gradients');
-
-    /**
-     * Disable custom font sizes in the editor.
-     * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#disabling-custom-font-sizes
-     */
-    add_theme_support('disable-custom-font-sizes');
-
     /**
      * Disable the default block patterns.
      * @link https://developer.wordpress.org/block-editor/developers/themes/theme-support/#disabling-the-default-block-patterns
diff --git a/style.css b/style.css
index 556600f..87c5ed8 100644
--- a/style.css
+++ b/style.css
@@ -9,5 +9,5 @@ Text Domain:        sage
 License:            MIT License
 License URI:        https://opensource.org/licenses/MIT
 Requires PHP:       7.4
-Requires at least:  5.4
+Requires at least:  5.9
 */
diff --git a/theme.json b/theme.json
new file mode 100644
index 0000000..e5b8e50
--- /dev/null
+++ b/theme.json
@@ -0,0 +1,38 @@
+{
+  "$schema": "https://schemas.wp.org/trunk/theme.json",
+  "version": 2,
+  "settings": {
+    "color": {
+      "palette": [
+        {
+          "slug": "primary",
+          "color": "#525ddc",
+          "name": "Primary"
+        }
+      ],
+      "custom": false,
+      "customGradient": false
+    },
+    "custom": {
+      "spacing": {},
+      "typography": {
+        "font-size": {},
+        "line-height": {}
+      }
+    },
+    "spacing": {
+      "padding": true,
+      "units": [
+        "px",
+        "%",
+        "em",
+        "rem",
+        "vw",
+        "vh"
+      ]
+    },
+    "typography": {
+      "customFontSize": false
+    }
+  }
+}