diff --git a/pyproject.toml b/pyproject.toml
index 6a48b27af..36c82e440 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,8 +22,8 @@ readme = "README.md"
 
 requires-python = ">=3.7"
 dependencies = [
-  "sphinx>=3,<5",
-  "pydata-sphinx-theme~=0.8.0",
+  "sphinx>=3,<6",
+  "pydata-sphinx-theme~=0.9.0",
   "pyyaml",
 ]
 
diff --git a/src/sphinx_book_theme/assets/styles/extensions/_ablog.scss b/src/sphinx_book_theme/assets/styles/extensions/_ablog.scss
index b8856560b..08a2e650e 100644
--- a/src/sphinx_book_theme/assets/styles/extensions/_ablog.scss
+++ b/src/sphinx_book_theme/assets/styles/extensions/_ablog.scss
@@ -26,7 +26,7 @@ ul.postlist {
 }
 
 // Sidebar rules specifically for ABlog
-div.bd-sidebar {
+div.bd-sidebar-primary {
   h2 {
     font-size: 1.5em;
   }
diff --git a/src/sphinx_book_theme/assets/styles/extensions/_readthedocs.scss b/src/sphinx_book_theme/assets/styles/extensions/_readthedocs.scss
index 16ed5a1d9..74dbf1363 100644
--- a/src/sphinx_book_theme/assets/styles/extensions/_readthedocs.scss
+++ b/src/sphinx_book_theme/assets/styles/extensions/_readthedocs.scss
@@ -1,9 +1,9 @@
 /**
  * ReadTheDocs pop-up menu over-rides.
- * We nest everything under `.bd-sidebar` so that we use more selective
+ * We nest everything under `.bd-sidebar-primary` so that we use more selective
  * selectors than what RTD CSS uses.
  */
-.bd-sidebar {
+.bd-sidebar-primary {
   // Parent container for everything else
   div#rtd-footer-container {
     position: sticky;
diff --git a/src/sphinx_book_theme/assets/styles/sections/_headers.scss b/src/sphinx_book_theme/assets/styles/sections/_headers.scss
index e85041587..548f73dbc 100644
--- a/src/sphinx_book_theme/assets/styles/sections/_headers.scss
+++ b/src/sphinx_book_theme/assets/styles/sections/_headers.scss
@@ -1,22 +1,10 @@
 /**
  * A few different header CSS rules
  */
-.header-item {
-  width: 100%;
-  text-align: center;
 
+// Remove this in the headers PR
+.header-item {
   &:empty {
     display: none;
   }
-
-  &.announcement {
-    background-color: #616161;
-    color: white;
-    padding: 0.4em 12.5%; // Horizontal padding so the width is 75%
-
-    @media (max-width: $breakpoint-md) {
-      // Announcements can take a bit more width on mobile
-      padding: 0.4em 2%;
-    }
-  }
 }
diff --git a/src/sphinx_book_theme/theme/sphinx_book_theme/layout.html b/src/sphinx_book_theme/theme/sphinx_book_theme/layout.html
index 37f19bce7..3ce29a602 100644
--- a/src/sphinx_book_theme/theme/sphinx_book_theme/layout.html
+++ b/src/sphinx_book_theme/theme/sphinx_book_theme/layout.html
@@ -16,38 +16,12 @@
     <div class="visually-hidden">Toggle in-page Table of Contents</div>
 </label>
 <!-- Headers at the top -->
-<div class="announcement header-item noprint">
-    {%- include "sections/announcement.html" -%}
-</div>
 <div class="header header-item noprint">
     {%- include "sections/header.html" -%}
 </div>
 {{ super() }}
 {% endblock %}
 
-<!-- Docs TOC is "d-none d-xl-block col-xl-2" -->
-{% block docs_sidebar %}
-<!-- Sidebar -->
-<div class="bd-sidebar noprint{% if is_single_page %} single-page{% endif %}" id="site-navigation">
-    {%- if not is_single_page %}
-    <div class="bd-sidebar__content">
-        <div class="bd-sidebar__top">
-            {%- include "sections/sidebar.html" -%}
-        </div>
-        <div class="bd-sidebar__bottom">
-            {% if theme_navbar_footer_text %}{% set theme_extra_navbar=theme_navbar_footer_text %}{% endif %} <!-- To handle the deprecated key -->
-            {% if theme_extra_navbar %}
-            <div class="navbar_extra_footer">
-            {{ theme_extra_navbar }}
-            </div>
-            {% endif %}
-        </div>
-    </div>
-    <div id="rtd-footer-container"></div>
-    {%- endif %}
-</div>
-{% endblock %}
-
 {% block docs_main %}
 <!-- A tiny helper pixel to detect if we've scrolled -->
 <div class="sbt-scroll-pixel-helper"></div>
diff --git a/src/sphinx_book_theme/theme/sphinx_book_theme/sections/footer-article.html b/src/sphinx_book_theme/theme/sphinx_book_theme/sections/footer-article.html
index 298225eb3..1c80c8bbd 100644
--- a/src/sphinx_book_theme/theme/sphinx_book_theme/sections/footer-article.html
+++ b/src/sphinx_book_theme/theme/sphinx_book_theme/sections/footer-article.html
@@ -1,4 +1,4 @@
 {%- if theme_show_prev_next -%}
-    {# stored in _templates because we inherit from the pydata theme #}
-    {% include "_templates/prev-next.html" %}
+    {# Inherited from the pydata theme #}
+    {% include "components/footer-article/prev-next.html" %}
 {%- endif -%}
diff --git a/src/sphinx_book_theme/theme/sphinx_book_theme/sections/sidebar-primary.html b/src/sphinx_book_theme/theme/sphinx_book_theme/sections/sidebar-primary.html
new file mode 100644
index 000000000..df94ef09c
--- /dev/null
+++ b/src/sphinx_book_theme/theme/sphinx_book_theme/sections/sidebar-primary.html
@@ -0,0 +1,22 @@
+{# This overrides the pydata theme sidebar template #}
+{% block docs_sidebar %}
+<!-- Sidebar -->
+<div class="bd-sidebar noprint{% if is_single_page %} single-page{% endif %}" id="site-navigation">
+    {%- if not is_single_page %}
+    <div class="bd-sidebar__content">
+        <div class="bd-sidebar__top">
+            {%- include "sections/sidebar.html" -%}
+        </div>
+        <div class="bd-sidebar__bottom">
+            {% if theme_navbar_footer_text %}{% set theme_extra_navbar=theme_navbar_footer_text %}{% endif %} <!-- To handle the deprecated key -->
+            {% if theme_extra_navbar %}
+            <div class="navbar_extra_footer">
+            {{ theme_extra_navbar }}
+            </div>
+            {% endif %}
+        </div>
+    </div>
+    <div id="rtd-footer-container"></div>
+    {%- endif %}
+</div>
+{% endblock %}
diff --git a/src/sphinx_book_theme/theme/sphinx_book_theme/sections/sidebar-secondary.html b/src/sphinx_book_theme/theme/sphinx_book_theme/sections/sidebar-secondary.html
new file mode 100644
index 000000000..8abb33f06
--- /dev/null
+++ b/src/sphinx_book_theme/theme/sphinx_book_theme/sections/sidebar-secondary.html
@@ -0,0 +1 @@
+{# Making this empty so it overrides the pydata theme #}