diff --git a/src/Drupal/Driver/DrupalDriver.php b/src/Drupal/Driver/DrupalDriver.php
index 6ed0325d..a4aad63b 100644
--- a/src/Drupal/Driver/DrupalDriver.php
+++ b/src/Drupal/Driver/DrupalDriver.php
@@ -23,7 +23,7 @@ class DrupalDriver implements DrupalDriverInterface {
   /**
    * Drupal core object.
    */
-  public CoreInterface $core;
+  protected CoreInterface $core;
 
   /**
    * System path to the Drupal installation.
@@ -38,7 +38,7 @@ class DrupalDriver implements DrupalDriverInterface {
   /**
    * Drupal core version.
    */
-  public int $version;
+  protected int $version;
 
   /**
    * Set Drupal root and URI.
@@ -93,36 +93,12 @@ public function processBatch(): void {
   }
 
   /**
-   * Determine major Drupal version.
-   *
-   * @return int
-   *   The major Drupal version.
-   *
-   * @throws \Drupal\Driver\Exception\BootstrapException
-   *   Thrown when the Drupal version could not be determined.
-   *
-   * @see drush_drupal_version()
+   * {@inheritdoc}
    */
   public function getDrupalVersion(): int {
     return $this->version;
   }
 
-  /**
-   * Injects the active Core implementation.
-   *
-   * Consumers override the driver's default Core lookup by passing any
-   * class that implements 'CoreInterface' - the class name and namespace
-   * do not matter. Typically called in a test bootstrap when the project
-   * ships its own Core subclass (e.g. one that registers additional field
-   * handlers in its 'registerDefaultFieldHandlers()' override).
-   *
-   * @param \Drupal\Driver\Core\CoreInterface $core
-   *   The Core instance the driver should delegate to.
-   */
-  public function setCore(CoreInterface $core): void {
-    $this->core = $core;
-  }
-
   /**
    * Automatically set the core from the current version.
    *
@@ -155,12 +131,19 @@ public function setCoreFromVersion(): void {
   }
 
   /**
-   * Return current core.
+   * {@inheritdoc}
    */
   public function getCore(): CoreInterface {
     return $this->core;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function setCore(CoreInterface $core): void {
+    $this->core = $core;
+  }
+
   /**
    * {@inheritdoc}
    */
diff --git a/src/Drupal/Driver/DrupalDriverInterface.php b/src/Drupal/Driver/DrupalDriverInterface.php
index 7d24cba2..a5d98e89 100644
--- a/src/Drupal/Driver/DrupalDriverInterface.php
+++ b/src/Drupal/Driver/DrupalDriverInterface.php
@@ -17,6 +17,7 @@
 use Drupal\Driver\Capability\RoleCapabilityInterface;
 use Drupal\Driver\Capability\UserCapabilityInterface;
 use Drupal\Driver\Capability\WatchdogCapabilityInterface;
+use Drupal\Driver\Core\CoreInterface;
 
 /**
  * Contract for the full-featured Drupal driver.
@@ -40,4 +41,36 @@ interface DrupalDriverInterface extends
   UserCapabilityInterface,
   WatchdogCapabilityInterface {
 
+  /**
+   * Return current core.
+   */
+  public function getCore(): CoreInterface;
+
+  /**
+   * Injects the active Core implementation.
+   *
+   * Consumers override the driver's default Core lookup by passing any
+   * class that implements 'CoreInterface' - the class name and namespace
+   * do not matter. Typically called in a test bootstrap when the project
+   * ships its own Core subclass (e.g. one that registers additional field
+   * handlers in its 'registerDefaultFieldHandlers()' override).
+   *
+   * @param \Drupal\Driver\Core\CoreInterface $core
+   *   The Core instance the driver should delegate to.
+   */
+  public function setCore(CoreInterface $core): void;
+
+  /**
+   * Returns the major Drupal version detected at construction time.
+   *
+   * The version is captured once when the driver is instantiated; the
+   * detection itself may throw BootstrapException, but this getter does not.
+   *
+   * @return int
+   *   The major Drupal version.
+   *
+   * @see drush_drupal_version()
+   */
+  public function getDrupalVersion(): int;
+
 }
diff --git a/tests/Drupal/Tests/Driver/Unit/CoreLookupTest.php b/tests/Drupal/Tests/Driver/Unit/CoreLookupTest.php
index 2f4b6786..055213ee 100644
--- a/tests/Drupal/Tests/Driver/Unit/CoreLookupTest.php
+++ b/tests/Drupal/Tests/Driver/Unit/CoreLookupTest.php
@@ -75,7 +75,8 @@ protected function createDriverWithVersion(int $version): DrupalDriver {
     $uri_prop = $reflection->getProperty('uri');
     $uri_prop->setValue($driver, 'default');
 
-    $driver->version = $version;
+    $version_property = $reflection->getProperty('version');
+    $version_property->setValue($driver, $version);
 
     return $driver;
   }
diff --git a/tests/Drupal/Tests/Driver/Unit/DrupalDriverDelegationTest.php b/tests/Drupal/Tests/Driver/Unit/DrupalDriverDelegationTest.php
index 93c2aa04..ea656b07 100644
--- a/tests/Drupal/Tests/Driver/Unit/DrupalDriverDelegationTest.php
+++ b/tests/Drupal/Tests/Driver/Unit/DrupalDriverDelegationTest.php
@@ -202,8 +202,10 @@ protected function createDriverWithCore(CoreInterface $core, int $version = 11):
     $uri = $reflection->getProperty('uri');
     $uri->setValue($driver, 'default');
 
-    $driver->version = $version;
-    $driver->core = $core;
+    $version_property = $reflection->getProperty('version');
+    $version_property->setValue($driver, $version);
+
+    $driver->setCore($core);
 
     return $driver;
   }