diff --git a/.github/workflows/install-testing.yml b/.github/workflows/install-testing.yml
index f40f044586c88..f347958e8b4ae 100644
--- a/.github/workflows/install-testing.yml
+++ b/.github/workflows/install-testing.yml
@@ -90,11 +90,13 @@ jobs:
             db-version: '8.4'
           - php: '7.3'
             db-version: '8.4'
+          # Only test the latest innovation release.
+          - db-version: '9.0'
           # MySQL 9.0+ will not work on PHP 7.2 & 7.3. See https://core.trac.wordpress.org/ticket/61218.
           - php: '7.2'
-            db-version: '9.0'
+            db-version: '9.1'
           - php: '7.3'
-            db-version: '9.0'
+            db-version: '9.1'
 
     services:
       database:
diff --git a/.github/workflows/local-docker-environment.yml b/.github/workflows/local-docker-environment.yml
index 17d078198c009..09b212e90ead5 100644
--- a/.github/workflows/local-docker-environment.yml
+++ b/.github/workflows/local-docker-environment.yml
@@ -90,11 +90,13 @@ jobs:
         exclude:
           # MySQL containers <= 5.5 do not exist or fail to start properly.
           - db-version: '5.5'
+          # Only test the latest innovation release.
+          - db-version: '9.0'
           # MySQL 9.0+ will not work on PHP 7.2 & 7.3. See https://core.trac.wordpress.org/ticket/61218.
           - php: '7.2'
-            db-version: '9.0'
+            db-version: '9.1'
           - php: '7.3'
-            db-version: '9.0'
+            db-version: '9.1'
 
     with:
       os: ${{ matrix.os }}
diff --git a/.github/workflows/phpunit-tests.yml b/.github/workflows/phpunit-tests.yml
index 3ea45fcdc331e..f52ce971e5489 100644
--- a/.github/workflows/phpunit-tests.yml
+++ b/.github/workflows/phpunit-tests.yml
@@ -36,7 +36,7 @@ jobs:
   #
   test-with-mysql:
     name: PHP ${{ matrix.php }}
-    uses: WordPress/wordpress-develop/.github/workflows/reusable-phpunit-tests-v3.yml@trunk
+    uses: ./.github/workflows/reusable-phpunit-tests-v3.yml
     permissions:
       contents: read
     secrets: inherit
@@ -47,7 +47,7 @@ jobs:
         os: [ ubuntu-latest ]
         php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
         db-type: [ 'mysql' ]
-        db-version: [ '5.7', '8.0', '8.4', '9.0' ]
+        db-version: [ '5.7', '8.0', '8.4' ]
         tests-domain: [ 'example.org' ]
         multisite: [ false, true ]
         memcached: [ false ]
@@ -91,14 +91,6 @@ jobs:
             multisite: false
             memcached: false
             report: true
-
-        exclude:
-          # MySQL 9.0+ will not work on PHP 7.2 & 7.3. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '9.0'
-          - php: '7.3'
-            db-version: '9.0'
-
     with:
       os: ${{ matrix.os }}
       php: ${{ matrix.php }}
@@ -115,7 +107,7 @@ jobs:
   #
   test-with-mariadb:
     name: PHP ${{ matrix.php }}
-    uses: WordPress/wordpress-develop/.github/workflows/reusable-phpunit-tests-v3.yml@trunk
+    uses: ./.github/workflows/reusable-phpunit-tests-v3.yml
     permissions:
       contents: read
     secrets: inherit
@@ -126,7 +118,7 @@ jobs:
         os: [ ubuntu-latest ]
         php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
         db-type: [ 'mariadb' ]
-        db-version: [ '10.4', '10.6', '10.11', '11.2' ]
+        db-version: [ '5.5', '10.3', '10.4', '10.5', '10.6', '10.11', '11.4' ]
         multisite: [ false, true ]
         memcached: [ false ]
 
@@ -135,13 +127,13 @@ jobs:
         - os: ubuntu-latest
           php: '8.3'
           db-type: 'mariadb'
-          db-version: '11.2'
+          db-version: '11.4'
           multisite: false
           memcached: true
         - os: ubuntu-latest
           php: '8.3'
           db-type: 'mariadb'
-          db-version: '11.2'
+          db-version: '11.4'
           multisite: true
           memcached: true
     with:
@@ -154,12 +146,61 @@ jobs:
       phpunit-config: ${{ matrix.multisite && 'tests/phpunit/multisite.xml' || 'phpunit.xml.dist' }}
       report: ${{ matrix.report || false }}
 
+  #
+  # Creates PHPUnit test jobs to test MariaDB and MySQL innovation releases.
+  #
+  # Though innovation releases are deemed "production grade" and never receive LTS status, they include new features
+  # and updates that will be included in the next LTS version.
+  #
+  # Because upstream support for innovation releases gets dropped when a new one is released, only the most recent
+  # innovation version is tested.
+  #
+  test-innovation-releases:
+    name: PHP ${{ matrix.php }}
+    uses: ./.github/workflows/reusable-phpunit-tests-v3.yml
+    permissions:
+      contents: read
+    secrets: inherit
+    if: ${{ github.repository == 'WordPress/wordpress-develop' || github.event_name == 'pull_request' }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ ubuntu-latest ]
+        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
+        db-type: [ 'mysql', 'mariadb' ]
+        db-version: [ '9.1', '11.6' ]
+        multisite: [ false, true ]
+        memcached: [ false ]
+        db-innovation: [ true ]
+
+        exclude:
+          # MySQL 9.0+ will not work on PHP <= 7.3 because mysql_native_password was removed. See https://core.trac.wordpress.org/ticket/61218.
+          - php: '7.2'
+            db-version: '9.1'
+          - php: '7.3'
+            db-version: '9.1'
+          # Exclude version combinations that don't exist.
+          - db-type: 'mariadb'
+            db-version: '9.1'
+          - db-type: 'mysql'
+            db-version: '11.6'
+    with:
+      os: ${{ matrix.os }}
+      php: ${{ matrix.php }}
+      db-type: ${{ matrix.db-type }}
+      db-version: ${{ matrix.db-version }}
+      db-innovation: ${{ matrix.db-innovation }}
+      multisite: ${{ matrix.multisite }}
+      memcached: ${{ matrix.memcached }}
+      phpunit-config: ${{ matrix.multisite && 'tests/phpunit/multisite.xml' || 'phpunit.xml.dist' }}
+      report: ${{ matrix.report || false }}
+
   #
   # Runs specific individual test groups.
   #
   specific-test-groups:
     name: ${{ matrix.phpunit-test-groups }}
-    uses: WordPress/wordpress-develop/.github/workflows/reusable-phpunit-tests-v3.yml@trunk
+    uses: ./.github/workflows/reusable-phpunit-tests-v3.yml
     permissions:
       contents: read
     secrets: inherit
@@ -183,7 +224,7 @@ jobs:
     permissions:
       actions: read
       contents: read
-    needs: [ test-with-mysql, test-with-mariadb, specific-test-groups ]
+    needs: [ test-with-mysql, test-with-mariadb, test-innovation-releases, specific-test-groups ]
     if: ${{ github.repository == 'WordPress/wordpress-develop' && github.event_name != 'pull_request' && always() }}
     with:
       calling_status: ${{ contains( needs.*.result, 'cancelled' ) && 'cancelled' || contains( needs.*.result, 'failure' ) && 'failure' || 'success' }}
diff --git a/.github/workflows/reusable-phpunit-tests-v3.yml b/.github/workflows/reusable-phpunit-tests-v3.yml
index cac3015af383a..3d26efa7026b2 100644
--- a/.github/workflows/reusable-phpunit-tests-v3.yml
+++ b/.github/workflows/reusable-phpunit-tests-v3.yml
@@ -27,6 +27,11 @@ on:
         required: false
         type: 'string'
         default: '8.4'
+      db-innovation:
+        description: 'Whether a database software innovation release is being tested.'
+        required: false
+        type: 'boolean'
+        default: false
       multisite:
         description: 'Whether to run tests as multisite'
         required: false
@@ -105,7 +110,7 @@ jobs:
   # - Checks out the WordPress Test reporter repository.
   # - Submit the test results to the WordPress.org host test results.
   phpunit-tests:
-    name: ${{ inputs.phpunit-test-groups && format( '{0} / ', inputs.phpunit-test-groups ) || '' }}PHP ${{ inputs.php }} ${{ ! inputs.phpunit-test-groups && ! inputs.coverage-report && '/ ' || 'with ' }}${{ 'mariadb' == inputs.db-type && 'MariaDB' || 'MySQL' }} ${{ inputs.db-version }}${{ inputs.multisite && ' multisite' || '' }}${{ inputs.memcached && ' with memcached' || '' }}${{ inputs.report && ' (test reporting enabled)' || '' }} ${{ 'example.org' != inputs.tests-domain && inputs.tests-domain || '' }}
+    name: ${{ inputs.phpunit-test-groups && format( '{0} / ', inputs.phpunit-test-groups ) || '' }}PHP ${{ inputs.php }} ${{ ! inputs.phpunit-test-groups && ! inputs.coverage-report && '/ ' || 'with ' }}${{ 'mariadb' == inputs.db-type && 'MariaDB' || 'MySQL' }} ${{ inputs.db-version }}${{ inputs.multisite && ' multisite' || '' }}${{ inputs.db-innovation && ' (innovation release)' || '' }}${{ inputs.memcached && ' with memcached' || '' }}${{ inputs.report && ' (test reporting enabled)' || '' }} ${{ 'example.org' != inputs.tests-domain && inputs.tests-domain || '' }}
     runs-on: ${{ inputs.os }}
     timeout-minutes: ${{ inputs.coverage-report && 120 || 20 }}
 
diff --git a/.version-support-mysql.json b/.version-support-mysql.json
index f6cffac449cae..8616ffb294e43 100644
--- a/.version-support-mysql.json
+++ b/.version-support-mysql.json
@@ -1,5 +1,6 @@
 {
 	"6-8": [
+		"9.1",
 		"9.0",
 		"8.4",
 		"8.0",
diff --git a/tests/phpunit/tests/db.php b/tests/phpunit/tests/db.php
index 3e06afcc1bf2c..57f5db65a2f5a 100644
--- a/tests/phpunit/tests/db.php
+++ b/tests/phpunit/tests/db.php
@@ -296,7 +296,7 @@ public function test_set_sql_mode() {
 		$check_new_modes = $wpdb->get_var( 'SELECT @@SESSION.sql_mode;' );
 		$this->assertSameSets( $new_modes, explode( ',', $check_new_modes ) );
 
-		$wpdb->set_sql_mode( explode( ',', $current_modes ) );
+		$wpdb->set_sql_mode( empty( $current_modes ) ? array() : explode( ',', $current_modes ) );
 	}
 
 	/**