diff --git a/.travis.yml b/.travis.yml
index 215bc3f..8c37c6c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -40,7 +40,7 @@ before_script:
   # aliasing current branch as `master`, since otherwise composer cannot determine the current branch-alias
   - git branch -D master || true
   - git checkout -b master
-  - composer self-update
+  - if [[ $DEPENDENCIES = '--no-scripts' ]]; then composer self-update --2; else composer self-update; fi
   - if [[ $LOCKED_DEPENDENCIES = '1' ]]; then composer install; fi
   - if [[ $LOCKED_DEPENDENCIES = '' ]]; then composer update $DEPENDENCIES; fi
 
diff --git a/composer.json b/composer.json
index 82a535e..d5a40da 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
         "composer-plugin-api": "^1.1.0 || ^2.0"
     },
     "replace": {
-        "ocramius/package-versions": "1.10.99"
+        "ocramius/package-versions": "1.11.99"
     },
     "require-dev": {
         "phpunit/phpunit":          "^6.5 || ^7",
diff --git a/src/PackageVersions/Installer.php b/src/PackageVersions/Installer.php
index a0a2616..b87a7b1 100644
--- a/src/PackageVersions/Installer.php
+++ b/src/PackageVersions/Installer.php
@@ -43,6 +43,8 @@ final class Installer implements PluginInterface, EventSubscriberInterface
 use Composer\InstalledVersions;
 use OutOfBoundsException;
 
+class_exists(InstalledVersions::class);
+
 /**
  * This class is generated by composer/package-versions-deprecated, specifically by
  * @see \PackageVersions\Installer
@@ -54,9 +56,7 @@ final class Installer implements PluginInterface, EventSubscriberInterface
 %s
 {
     /**
-     * @deprecated please use {@see \Composer\InstalledVersions::getRootPackage()} instead. The
-     *             equivalent expression for this constant's contents is
-     *             `\Composer\InstalledVersions::getRootPackage()['name']`.
+     * @deprecated please use {@see self::rootPackageName()} instead.
      *             This constant will be removed in version 2.0.0.
      */
     const ROOT_PACKAGE_NAME = '%s';
@@ -72,7 +72,21 @@ final class Installer implements PluginInterface, EventSubscriberInterface
 
     private function __construct()
     {
-        class_exists(InstalledVersions::class);
+    }
+
+    /**
+     * @psalm-pure
+     *
+     * @psalm-suppress ImpureMethodCall we know that {@see InstalledVersions} interaction does not
+     *                                  cause any side effects here.
+     */
+    public static function rootPackageName() : string
+    {
+        if (!class_exists(InstalledVersions::class, false) || !InstalledVersions::getRawData()) {
+            return self::ROOT_PACKAGE_NAME;
+        }
+
+        return InstalledVersions::getRootPackage()['name'];
     }
 
     /**
@@ -86,7 +100,7 @@ class_exists(InstalledVersions::class);
      */
     public static function getVersion(string $packageName): string
     {
-        if (class_exists(InstalledVersions::class, false)) {
+        if (class_exists(InstalledVersions::class, false) && InstalledVersions::getRawData()) {
             return InstalledVersions::getPrettyVersion($packageName)
                 . '@' . InstalledVersions::getReference($packageName);
         }
diff --git a/src/PackageVersions/Versions.php b/src/PackageVersions/Versions.php
index 2446cc1..e1cca5d 100644
--- a/src/PackageVersions/Versions.php
+++ b/src/PackageVersions/Versions.php
@@ -8,6 +8,8 @@
 use OutOfBoundsException;
 use UnexpectedValueException;
 
+class_exists(InstalledVersions::class);
+
 /**
  * This is a stub class: it is in place only for scenarios where PackageVersions
  * is installed with a `--no-scripts` flag, in which scenarios the Versions class
@@ -19,17 +21,31 @@
 final class Versions
 {
     /**
-     * @deprecated please use {@see \Composer\InstalledVersions::getRootPackage()} instead. The
-     *             equivalent expression for this constant's contents is
-     *             `\Composer\InstalledVersions::getRootPackage()['name']`.
+     * @deprecated please use {@see self::rootPackageName()} instead.
      *             This constant will be removed in version 2.0.0.
      */
-    const ROOT_PACKAGE_NAME = FallbackVersions::ROOT_PACKAGE_NAME;
+    const ROOT_PACKAGE_NAME = 'unknown/root-package@UNKNOWN';
+
+    /** @internal */
     const VERSIONS          = [];
 
     private function __construct()
     {
-        class_exists(InstalledVersions::class);
+    }
+
+    /**
+     * @psalm-pure
+     *
+     * @psalm-suppress ImpureMethodCall we know that {@see InstalledVersions} interaction does not
+     *                                  cause any side effects here.
+     */
+    public static function rootPackageName() : string
+    {
+        if (!class_exists(InstalledVersions::class, false) || !InstalledVersions::getRawData()) {
+            return self::ROOT_PACKAGE_NAME;
+        }
+
+        return InstalledVersions::getRootPackage()['name'];
     }
 
     /**
@@ -38,10 +54,17 @@ class_exists(InstalledVersions::class);
      */
     public static function getVersion(string $packageName): string
     {
-        if (!class_exists(InstalledVersions::class, false)) {
+        if (!class_exists(InstalledVersions::class, false) || !InstalledVersions::getRawData()) {
             return FallbackVersions::getVersion($packageName);
         }
 
+        /** @psalm-suppress DeprecatedConstant */
+        if ($packageName === self::ROOT_PACKAGE_NAME) {
+            $rootPackage = InstalledVersions::getRootPackage();
+
+            return $rootPackage['pretty_version'] . '@' . $rootPackage['reference'];
+        }
+
         return InstalledVersions::getPrettyVersion($packageName)
             . '@' . InstalledVersions::getReference($packageName);
     }
diff --git a/test/PackageVersionsTest/InstallerTest.php b/test/PackageVersionsTest/InstallerTest.php
index a9312b9..cd06171 100644
--- a/test/PackageVersionsTest/InstallerTest.php
+++ b/test/PackageVersionsTest/InstallerTest.php
@@ -269,6 +269,8 @@ public function testDumpVersionsClass()
 use Composer\InstalledVersions;
 use OutOfBoundsException;
 
+class_exists(InstalledVersions::class);
+
 /**
  * This class is generated by composer/package-versions-deprecated, specifically by
  * @see \PackageVersions\Installer
@@ -280,9 +282,7 @@ public function testDumpVersionsClass()
 final class Versions
 {
     /**
-     * @deprecated please use {@see \Composer\InstalledVersions::getRootPackage()} instead. The
-     *             equivalent expression for this constant's contents is
-     *             `\Composer\InstalledVersions::getRootPackage()['name']`.
+     * @deprecated please use {@see self::rootPackageName()} instead.
      *             This constant will be removed in version 2.0.0.
      */
     const ROOT_PACKAGE_NAME = 'root/package';
@@ -305,7 +305,21 @@ final class Versions
 
     private function __construct()
     {
-        class_exists(InstalledVersions::class);
+    }
+
+    /**
+     * @psalm-pure
+     *
+     * @psalm-suppress ImpureMethodCall we know that {@see InstalledVersions} interaction does not
+     *                                  cause any side effects here.
+     */
+    public static function rootPackageName() : string
+    {
+        if (!class_exists(InstalledVersions::class, false) || !InstalledVersions::getRawData()) {
+            return self::ROOT_PACKAGE_NAME;
+        }
+
+        return InstalledVersions::getRootPackage()['name'];
     }
 
     /**
@@ -319,7 +333,7 @@ class_exists(InstalledVersions::class);
      */
     public static function getVersion(string $packageName): string
     {
-        if (class_exists(InstalledVersions::class, false)) {
+        if (class_exists(InstalledVersions::class, false) && InstalledVersions::getRawData()) {
             return InstalledVersions::getPrettyVersion($packageName)
                 . '@' . InstalledVersions::getReference($packageName);
         }
@@ -404,6 +418,8 @@ public function testDumpVersionsClassNoDev()
 use Composer\InstalledVersions;
 use OutOfBoundsException;
 
+class_exists(InstalledVersions::class);
+
 /**
  * This class is generated by composer/package-versions-deprecated, specifically by
  * @see \PackageVersions\Installer
@@ -415,9 +431,7 @@ public function testDumpVersionsClassNoDev()
 final class Versions
 {
     /**
-     * @deprecated please use {@see \Composer\InstalledVersions::getRootPackage()} instead. The
-     *             equivalent expression for this constant's contents is
-     *             `\Composer\InstalledVersions::getRootPackage()['name']`.
+     * @deprecated please use {@see self::rootPackageName()} instead.
      *             This constant will be removed in version 2.0.0.
      */
     const ROOT_PACKAGE_NAME = 'root/package';
@@ -439,7 +453,21 @@ final class Versions
 
     private function __construct()
     {
-        class_exists(InstalledVersions::class);
+    }
+
+    /**
+     * @psalm-pure
+     *
+     * @psalm-suppress ImpureMethodCall we know that {@see InstalledVersions} interaction does not
+     *                                  cause any side effects here.
+     */
+    public static function rootPackageName() : string
+    {
+        if (!class_exists(InstalledVersions::class, false) || !InstalledVersions::getRawData()) {
+            return self::ROOT_PACKAGE_NAME;
+        }
+
+        return InstalledVersions::getRootPackage()['name'];
     }
 
     /**
@@ -453,7 +481,7 @@ class_exists(InstalledVersions::class);
      */
     public static function getVersion(string $packageName): string
     {
-        if (class_exists(InstalledVersions::class, false)) {
+        if (class_exists(InstalledVersions::class, false) && InstalledVersions::getRawData()) {
             return InstalledVersions::getPrettyVersion($packageName)
                 . '@' . InstalledVersions::getReference($packageName);
         }
@@ -542,6 +570,8 @@ public function testDumpVersionsWithoutPackageSourceDetails()
 use Composer\InstalledVersions;
 use OutOfBoundsException;
 
+class_exists(InstalledVersions::class);
+
 /**
  * This class is generated by composer/package-versions-deprecated, specifically by
  * @see \PackageVersions\Installer
@@ -553,9 +583,7 @@ public function testDumpVersionsWithoutPackageSourceDetails()
 final class Versions
 {
     /**
-     * @deprecated please use {@see \Composer\InstalledVersions::getRootPackage()} instead. The
-     *             equivalent expression for this constant's contents is
-     *             `\Composer\InstalledVersions::getRootPackage()['name']`.
+     * @deprecated please use {@see self::rootPackageName()} instead.
      *             This constant will be removed in version 2.0.0.
      */
     const ROOT_PACKAGE_NAME = 'root/package';
@@ -577,7 +605,21 @@ final class Versions
 
     private function __construct()
     {
-        class_exists(InstalledVersions::class);
+    }
+
+    /**
+     * @psalm-pure
+     *
+     * @psalm-suppress ImpureMethodCall we know that {@see InstalledVersions} interaction does not
+     *                                  cause any side effects here.
+     */
+    public static function rootPackageName() : string
+    {
+        if (!class_exists(InstalledVersions::class, false) || !InstalledVersions::getRawData()) {
+            return self::ROOT_PACKAGE_NAME;
+        }
+
+        return InstalledVersions::getRootPackage()['name'];
     }
 
     /**
@@ -591,7 +633,7 @@ class_exists(InstalledVersions::class);
      */
     public static function getVersion(string $packageName): string
     {
-        if (class_exists(InstalledVersions::class, false)) {
+        if (class_exists(InstalledVersions::class, false) && InstalledVersions::getRawData()) {
             return InstalledVersions::getPrettyVersion($packageName)
                 . '@' . InstalledVersions::getReference($packageName);
         }
@@ -973,6 +1015,8 @@ public function testGetVersionsIsNotNormalizedForRootPackage()
 use Composer\InstalledVersions;
 use OutOfBoundsException;
 
+class_exists(InstalledVersions::class);
+
 /**
  * This class is generated by composer/package-versions-deprecated, specifically by
  * @see \PackageVersions\Installer
@@ -984,9 +1028,7 @@ public function testGetVersionsIsNotNormalizedForRootPackage()
 final class Versions
 {
     /**
-     * @deprecated please use {@see \Composer\InstalledVersions::getRootPackage()} instead. The
-     *             equivalent expression for this constant's contents is
-     *             `\Composer\InstalledVersions::getRootPackage()['name']`.
+     * @deprecated please use {@see self::rootPackageName()} instead.
      *             This constant will be removed in version 2.0.0.
      */
     const ROOT_PACKAGE_NAME = 'root/package';
@@ -1006,7 +1048,21 @@ final class Versions
 
     private function __construct()
     {
-        class_exists(InstalledVersions::class);
+    }
+
+    /**
+     * @psalm-pure
+     *
+     * @psalm-suppress ImpureMethodCall we know that {@see InstalledVersions} interaction does not
+     *                                  cause any side effects here.
+     */
+    public static function rootPackageName() : string
+    {
+        if (!class_exists(InstalledVersions::class, false) || !InstalledVersions::getRawData()) {
+            return self::ROOT_PACKAGE_NAME;
+        }
+
+        return InstalledVersions::getRootPackage()['name'];
     }
 
     /**
@@ -1020,7 +1076,7 @@ class_exists(InstalledVersions::class);
      */
     public static function getVersion(string $packageName): string
     {
-        if (class_exists(InstalledVersions::class, false)) {
+        if (class_exists(InstalledVersions::class, false) && InstalledVersions::getRawData()) {
             return InstalledVersions::getPrettyVersion($packageName)
                 . '@' . InstalledVersions::getReference($packageName);
         }
diff --git a/test/PackageVersionsTest/VersionsTest.php b/test/PackageVersionsTest/VersionsTest.php
index f059bdc..3f63dc4 100644
--- a/test/PackageVersionsTest/VersionsTest.php
+++ b/test/PackageVersionsTest/VersionsTest.php
@@ -13,11 +13,7 @@
 use function json_decode;
 use function uniqid;
 
-/**
- * @uses \PackageVersions\FallbackVersions
- *
- * @covers \PackageVersions\Versions
- */
+/** @covers \PackageVersions\Versions */
 final class VersionsTest extends TestCase
 {
     public function testValidVersions()
@@ -36,6 +32,19 @@ public function testValidVersions()
         }
     }
 
+    /** @group #148 */
+    public function testCanRetrieveRootPackageVersion()
+    {
+        /** @psalm-suppress DeprecatedConstant */
+        self::assertRegExp('/^.+\@[0-9a-f]+$/', Versions::getVersion(Versions::ROOT_PACKAGE_NAME));
+    }
+
+    /** @group #153 */
+    public function testCanRetrieveRootPackageName()
+    {
+        self::assertRegExp('/^[a-z0-9\\-]+\\/[a-z0-9\\-]+$/', Versions::rootPackageName());
+    }
+
     public function testInvalidVersionsAreRejected()
     {
         $this->expectException(OutOfBoundsException::class);