diff --git a/.travis.yml b/.travis.yml
index 62e6af4..7edb4fc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,6 +18,9 @@ matrix:
   include:
     - php: 5.3
       env: COMPOSER_FLAGS="--prefer-lowest"
+    # Special case for https://github.com/Soullivaneuh/composer-versions-check/issues/8
+    - php: 5.6
+      env: WITHOUT_SEMVER=1
   allow_failures:
     - php: nightly
     - php: hhvm
@@ -29,14 +32,20 @@ cache:
   directories:
     - $HOME/.composer/cache/files
 
-before_script:
+before_install:
   - composer selfupdate
   - composer config -g github-oauth.github.com $GITHUB_OAUTH_TOKEN
   - composer global require phpunit/phpunit:^4.8 --no-update
-  - composer global update --prefer-dist --no-interaction
   - if [ "$PHP_CS_FIXER_VERSION" != "" ]; then composer require "fabpot/php-cs-fixer:${PHP_CS_FIXER_VERSION}" --no-update; fi;
+  - if [ "$WITHOUT_SEMVER" = 1 ]; then composer require "composer/composer:dev-master#013a748" --no-update; fi;
+
+install:
+  - composer global update --prefer-dist --no-interaction
   - composer update --prefer-dist --no-interaction $COMPOSER_FLAGS
 
+before_script:
+  - if [ "$WITHOUT_SEMVER" = 1 ]; then rm -rf vendor/composer/semver; fi;
+
 script: make test
 
 after_script:
diff --git a/src/VersionsCheck.php b/src/VersionsCheck.php
index 67ccd16..d891e86 100644
--- a/src/VersionsCheck.php
+++ b/src/VersionsCheck.php
@@ -2,6 +2,7 @@
 
 namespace SLLH\ComposerVersionsCheck;
 
+use Composer\Package\LinkConstraint\VersionConstraint;
 use Composer\Package\PackageInterface;
 use Composer\Package\RootPackageInterface;
 use Composer\Repository\ArrayRepository;
@@ -19,6 +20,11 @@ final class VersionsCheck
      */
     private $outdatedPackages = array();
 
+    /**
+     * @var VersionConstraint|null
+     */
+    private $oldComparator = null;
+
     /**
      * @param ArrayRepository             $distRepository
      * @param WritableRepositoryInterface $localRepository
@@ -30,8 +36,14 @@ public function checkPackages(ArrayRepository $distRepository, WritableRepositor
         /** @var PackageInterface[] $packages */
         $packages = $localRepository->getPackages();
         foreach ($packages as $package) {
+            // Old composer versions BC
+            $versionConstraint = class_exists('Composer\Semver\Constraint\Constraint')
+                ? new Constraint('>', $package->getVersion())
+                : new VersionConstraint('>', $package->getVersion())
+            ;
+
             /** @var PackageInterface[] $higherPackages */
-            $higherPackages = $distRepository->findPackages($package->getName(), new Constraint('>', $package->getVersion()));
+            $higherPackages = $distRepository->findPackages($package->getName(), $versionConstraint);
             // Remove not stable packages if unwanted
             if (true === $rootPackage->getPreferStable()) {
                 $higherPackages = array_filter($higherPackages, function (PackageInterface $package) {
@@ -41,7 +53,7 @@ public function checkPackages(ArrayRepository $distRepository, WritableRepositor
             if (count($higherPackages) > 0) {
                 // Sort packages by highest version to lowest
                 usort($higherPackages, function (PackageInterface $p1, PackageInterface $p2) {
-                    return Comparator::lessThan($p1->getVersion(), $p2->getVersion());
+                    return $this->versionCompare($p1->getVersion(), '<', $p2->getVersion());
                 });
                 // Push actual and last package on outdated array
                 array_push($this->outdatedPackages, new OutdatedPackage($package, $higherPackages[0]));
@@ -81,4 +93,24 @@ private function createNotUpToDateOutput(array &$output)
 
         $output[] = '';
     }
+
+    /**
+     * Version comparator bridge to handle BC with old composer versions.
+     *
+     * @param string $version1
+     * @param string $operator
+     * @param string $version2
+     *
+     * @return bool
+     */
+    private function versionCompare($version1, $operator, $version2)
+    {
+        if (!class_exists('Composer\Semver\Comparator')) {
+            $this->oldComparator = $this->oldComparator ?: new VersionConstraint('==', '1.0');
+
+            return $this->oldComparator->versionCompare($version1, $version2, $operator);
+        }
+
+        return Comparator::compare($version1, $operator, $version2);
+    }
 }