diff --git a/.tugboat/config.yml b/.tugboat/config.yml
index dc87a25d4e..b1b5f43a99 100644
--- a/.tugboat/config.yml
+++ b/.tugboat/config.yml
@@ -1,3 +1,4 @@
+# yaml-language-server: $schema=../vendor/symfony/dependency-injection/Loader/schema/services.schema.json
 services:
   # What to call the service hosting the site.
   php:
@@ -100,7 +101,7 @@ services:
         - PATH=${TUGBOAT_ROOT}/vendor/bin:$PATH ${TUGBOAT_ROOT}/scripts/ma-import-backup /tmp/database.sql.gz
         - rm -f /tmp/database.sql.gz
         # Set release for env indicator module
-        - drush sset environment_indicator.current_release ${TUGBOAT_GITHUB_HEAD} || true
+        - ${TUGBOAT_ROOT}/vendor/bin/drush sset environment_indicator.current_release ${TUGBOAT_GITHUB_HEAD} || true
         # Set file permissions such that Drupal will not complain.
         - chgrp -R www-data "${DOCROOT}/sites/default/files"
         - find "${DOCROOT}/sites/default/files" -type d -exec chmod 2775 {} \;
@@ -118,6 +119,8 @@ services:
         - composer install --no-interaction --optimize-autoloader --no-cache
         - yarn install
         - PATH=${TUGBOAT_ROOT}/vendor/bin:$PATH ${TUGBOAT_ROOT}/scripts/ma-refresh-local --skip-db-prep
+        # Set release for env indicator module (also in update step, but build runs alone for PR previews from base).
+        - ${TUGBOAT_ROOT}/vendor/bin/drush sset environment_indicator.current_release ${TUGBOAT_GITHUB_HEAD} || true
 
   # This 'mysql' key acts as the hostname to access the service by from the php service.
   mysql:
diff --git a/changelogs/DP-46272.yml b/changelogs/DP-46272.yml
new file mode 100644
index 0000000000..80d1bf14e5
--- /dev/null
+++ b/changelogs/DP-46272.yml
@@ -0,0 +1,3 @@
+Fixed:
+  - description: Fix missing tag number in environment indicator after D11 upgrade.
+    issue: DP-46272
diff --git a/composer.json b/composer.json
index 068ba3f646..308e3ea3b8 100644
--- a/composer.json
+++ b/composer.json
@@ -541,6 +541,9 @@
             },
             "drupal/editoria11y": {
                 "Fix result name options to use editoria11y_results table instead of editoria11y_dismissals (DP-42700)": "patches/editoria11y--result-name-options-results.patch"
+            },
+            "drupal/environment_indicator": {
+                "Fix getVersionIdentifier() to return NULL instead of empty string (https://www.drupal.org/project/environment_indicator/issues/3535382)": "patches/environment_indicator_getVersionIdentifier_return_null_3535382.patch"
             }
         },
         "composer-exit-on-patch-failure": true,
diff --git a/composer.lock b/composer.lock
index ed96f99206..12ddb30da9 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "a6d89ea2953b3ffae673bc55fc09ebb3",
+    "content-hash": "1f4ed688d02b82a8256a0bc070a63651",
     "packages": [
         {
             "name": "akamai-open/edgegrid-auth",
diff --git a/conf/drupal/config/environment_indicator.settings.yml b/conf/drupal/config/environment_indicator.settings.yml
index e3bb7d552d..902b1ebfe7 100644
--- a/conf/drupal/config/environment_indicator.settings.yml
+++ b/conf/drupal/config/environment_indicator.settings.yml
@@ -2,5 +2,5 @@ _core:
   default_config_hash: Bi0EyyiH6m5wpHRfxlKhqTIhAZayhRQudheDzAcrotU
 toolbar_integration: {  }
 favicon: true
-version_identifier: environment_indicator_current_release
-version_identifier_fallback: deployment_identifier
+version_identifier: deployment_identifier
+version_identifier_fallback: environment_indicator_current_release
diff --git a/patches/environment_indicator_getVersionIdentifier_return_null_3535382.patch b/patches/environment_indicator_getVersionIdentifier_return_null_3535382.patch
new file mode 100644
index 0000000000..3eaca62128
--- /dev/null
+++ b/patches/environment_indicator_getVersionIdentifier_return_null_3535382.patch
@@ -0,0 +1,144 @@
+diff --git a/.cspell-project-words.txt b/.cspell-project-words.txt
+index 639dfec4bb0025d6e84d5e6b48409708ad966da1..7f6585956d4a6d89aabc180816d304332e9ec7c7 100644
+--- a/.cspell-project-words.txt
++++ b/.cspell-project-words.txt
+@@ -3,3 +3,4 @@ tinycon
+ mrfelton
+ isholgueras
+ trackleft2
++colour
+\ No newline at end of file
+diff --git a/src/Service/EnvironmentIndicator.php b/src/Service/EnvironmentIndicator.php
+index cef2f0bb5a3e0a40f57af71c4017075dbd8065a8..d94d45a1599d8d8d173e357ff7832cab20728f44 100644
+--- a/src/Service/EnvironmentIndicator.php
++++ b/src/Service/EnvironmentIndicator.php
+@@ -154,10 +154,10 @@ class EnvironmentIndicator {
+   protected function getVersionIdentifier(string $type): ?string {
+     switch ($type) {
+       case 'environment_indicator_current_release':
+-        return (string) $this->state->get('environment_indicator.current_release');
++        return !empty($this->state->get('environment_indicator.current_release')) ? (string) $this->state->get('environment_indicator.current_release') : NULL;
+
+       case 'deployment_identifier':
+-        return (string) $this->settings->get('deployment_identifier');
++        return !empty($this->settings->get('deployment_identifier')) ? (string) $this->settings->get('deployment_identifier') : NULL;
+
+       case 'drupal_version':
+         return \Drupal::VERSION;
+diff --git a/tests/src/Functional/EnvironmentIndicatorServiceTest.php b/tests/src/Functional/EnvironmentIndicatorServiceTest.php
+new file mode 100644
+index 0000000000000000000000000000000000000000..7f548bda215a50e19ca01befae740b66d6e47c0a
+--- /dev/null
++++ b/tests/src/Functional/EnvironmentIndicatorServiceTest.php
+@@ -0,0 +1,111 @@
++<?php
++
++declare(strict_types=1);
++
++namespace Drupal\Tests\environment_indicator\Functional;
++
++use Drupal\Tests\BrowserTestBase;
++
++/**
++ * Functional tests for the EnvironmentIndicator service.
++ *
++ * Tests the actual behavior of the service to validate that empty values
++ * are properly handled (should return NULL, not empty strings).
++ */
++class EnvironmentIndicatorServiceTest extends BrowserTestBase {
++
++  /**
++   * {@inheritdoc}
++   */
++  protected static $modules = [
++    'environment_indicator',
++  ];
++
++  /**
++   * {@inheritdoc}
++   */
++  protected $defaultTheme = 'stark';
++
++  /**
++   * The environment indicator service.
++   *
++   * @var \Drupal\environment_indicator\Service\EnvironmentIndicator
++   */
++  protected $environmentIndicatorService;
++
++  /**
++   * {@inheritdoc}
++   */
++  protected function setUp(): void {
++    parent::setUp();
++    $this->environmentIndicatorService = $this->container->get('environment_indicator.indicator');
++  }
++
++  /**
++   * Tests that empty state values are handled correctly.
++   *
++   * This test validates the behavior of getVersionIdentifier when
++   * environment_indicator.current_release is set to an empty string.
++   */
++  public function testEmptyStateValue(): void {
++    // Set empty string in state.
++    \Drupal::state()->set('environment_indicator.current_release', '');
++    // Create a user with permission.
++    $user = $this->drupalCreateUser(['view environment indicator current release']);
++    $this->drupalLogin($user);
++    $result = $this->environmentIndicatorService->getCurrentRelease();
++    // This assertion will FAIL with current implementation (returns '')
++    // and PASS after applying the fix (returns NULL)
++    $this->assertNull($result, 'Empty state value should return NULL, not empty string');
++  }
++
++  /**
++   * Tests that zero values are handled correctly.
++   *
++   * This test validates the behavior when state contains integer 0.
++   */
++  public function testZeroStateValue(): void {
++    // Set integer 0 in state.
++    \Drupal::state()->set('environment_indicator.current_release', 0);
++    // Create a user with permission.
++    $user = $this->drupalCreateUser(['view environment indicator current release']);
++    $this->drupalLogin($user);
++    $result = $this->environmentIndicatorService->getCurrentRelease();
++    $this->assertNull($result, 'Zero value should be treated as empty and return NULL');
++  }
++
++  /**
++   * Tests permission handling.
++   */
++  public function testPermissionHandling(): void {
++    // Set a value in state.
++    \Drupal::state()->set('environment_indicator.current_release', 'v1.0.0');
++    // Create a user WITHOUT the required permission.
++    $user = $this->drupalCreateUser([]);
++    $this->drupalLogin($user);
++    $result = $this->environmentIndicatorService->getCurrentRelease();
++    $this->assertNull($result, 'Should return NULL when user lacks permission');
++  }
++
++  /**
++   * Tests deployment_identifier with empty value.
++   *
++   * This test validates that empty deployment_identifier returns NULL.
++   */
++  public function testEmptyDeploymentIdentifier(): void {
++    // Configure to use deployment_identifier as primary.
++    $this->config('environment_indicator.settings')
++      ->set('version_identifier', 'deployment_identifier')
++      ->set('version_identifier_fallback', 'drupal_version')
++      ->save();
++    // Create a user with permission.
++    $user = $this->drupalCreateUser(['view environment indicator current release']);
++    $this->drupalLogin($user);
++    $result = $this->environmentIndicatorService->getCurrentRelease();
++    // Since deployment_identifier will be empty in test environment,
++    // this should fall back to drupal_version and return that.
++    $this->assertIsString($result, 'Should fall back to drupal_version when deployment_identifier is empty');
++    $this->assertNotEmpty($result, 'Drupal version should not be empty');
++  }
++
++}