diff --git a/.travis.yml b/.travis.yml
index 66b0e596ecea6..0cabd5b4e6898 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -158,7 +158,7 @@ install:
               echo "$COMPONENTS" | parallel --gnu "tfold {} $PHPUNIT_X {}"
               tfold tty-group $PHPUNIT --group tty
               if [[ $PHP = $MIN_PHP ]]; then
-                  echo -e "1\\n0" | xargs -I{} bash -c "tfold src/Symfony/Component/Process.sigchild{} SYMFONY_DEPRECATIONS_HELPER=weak ENHANCE_SIGCHLD={} php-$MIN_PHP/sapi/cli/php ./phpunit --colors=always src/Symfony/Component/Process/"
+                  tfold src/Symfony/Component/Process.sigchild SYMFONY_DEPRECATIONS_HELPER=weak php-$MIN_PHP/sapi/cli/php ./phpunit --colors=always src/Symfony/Component/Process/
               fi
           fi
       }
diff --git a/src/Symfony/Component/Process/Process.php b/src/Symfony/Component/Process/Process.php
index a34db920ef545..d0f6c0ce451e9 100644
--- a/src/Symfony/Component/Process/Process.php
+++ b/src/Symfony/Component/Process/Process.php
@@ -64,7 +64,6 @@ class Process implements \IteratorAggregate
     private $outputDisabled = false;
     private $stdout;
     private $stderr;
-    private $enhanceSigchildCompatibility;
     private $process;
     private $status = self::STATUS_READY;
     private $incrementalOutputOffset = 0;
@@ -165,7 +164,6 @@ public function __construct($commandline, $cwd = null, array $env = null, $input
         $this->setTimeout($timeout);
         $this->useFileHandles = '\\' === DIRECTORY_SEPARATOR;
         $this->pty = false;
-        $this->enhanceSigchildCompatibility = '\\' !== DIRECTORY_SEPARATOR && $this->isSigchildEnabled();
     }
 
     public function __destruct()
@@ -218,17 +216,12 @@ public function run($callback = null, array $env = array())
      *
      * @return self
      *
-     * @throws RuntimeException       if PHP was compiled with --enable-sigchild and the enhanced sigchild compatibility mode is not enabled
      * @throws ProcessFailedException if the process didn't terminate successfully
      *
      * @final since version 3.3
      */
     public function mustRun(callable $callback = null, array $env = array())
     {
-        if (!$this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
-            throw new RuntimeException('This PHP has been compiled with --enable-sigchild. You must use setEnhanceSigchildCompatibility() to use this method.');
-        }
-
         if (0 !== $this->run($callback, $env)) {
             throw new ProcessFailedException($this);
         }
@@ -297,7 +290,7 @@ public function start(callable $callback = null, array $env = array())
         if ('\\' === DIRECTORY_SEPARATOR) {
             $options['bypass_shell'] = true;
             $commandline = $this->prepareWindowsCommandLine($commandline, $envBackup, $env);
-        } elseif (!$this->useFileHandles && $this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
+        } elseif (!$this->useFileHandles && $this->isSigchildEnabled()) {
             // last exit code is output on the fourth pipe and caught to work around --enable-sigchild
             $descriptors[3] = array('pipe', 'w');
 
@@ -665,15 +658,9 @@ public function clearErrorOutput()
      * Returns the exit code returned by the process.
      *
      * @return null|int The exit status code, null if the Process is not terminated
-     *
-     * @throws RuntimeException In case --enable-sigchild is activated and the sigchild compatibility mode is disabled
      */
     public function getExitCode()
     {
-        if (!$this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
-            throw new RuntimeException('This PHP has been compiled with --enable-sigchild. You must use setEnhanceSigchildCompatibility() to use this method.');
-        }
-
         $this->updateStatus(false);
 
         return $this->exitcode;
@@ -716,17 +703,12 @@ public function isSuccessful()
      *
      * @return bool
      *
-     * @throws RuntimeException In case --enable-sigchild is activated
-     * @throws LogicException   In case the process is not terminated
+     * @throws LogicException In case the process is not terminated
      */
     public function hasBeenSignaled()
     {
         $this->requireProcessIsTerminated(__FUNCTION__);
 
-        if (!$this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
-            throw new RuntimeException('This PHP has been compiled with --enable-sigchild. Term signal can not be retrieved.');
-        }
-
         return $this->processInformation['signaled'];
     }
 
@@ -744,7 +726,7 @@ public function getTermSignal()
     {
         $this->requireProcessIsTerminated(__FUNCTION__);
 
-        if ($this->isSigchildEnabled() && (!$this->enhanceSigchildCompatibility || -1 === $this->processInformation['termsig'])) {
+        if ($this->isSigchildEnabled() && -1 === $this->processInformation['termsig']) {
             throw new RuntimeException('This PHP has been compiled with --enable-sigchild. Term signal can not be retrieved.');
         }
 
@@ -1153,42 +1135,6 @@ public function setInput($input)
         return $this;
     }
 
-    /**
-     * Returns whether sigchild compatibility mode is activated or not.
-     *
-     * @return bool
-     *
-     * @deprecated since version 3.3, to be removed in 4.0. Sigchild compatibility will always be enabled.
-     */
-    public function getEnhanceSigchildCompatibility()
-    {
-        @trigger_error(sprintf('The %s() method is deprecated since version 3.3 and will be removed in 4.0. Sigchild compatibility will always be enabled.', __METHOD__), E_USER_DEPRECATED);
-
-        return $this->enhanceSigchildCompatibility;
-    }
-
-    /**
-     * Activates sigchild compatibility mode.
-     *
-     * Sigchild compatibility mode is required to get the exit code and
-     * determine the success of a process when PHP has been compiled with
-     * the --enable-sigchild option
-     *
-     * @param bool $enhance
-     *
-     * @return self The current Process instance
-     *
-     * @deprecated since version 3.3, to be removed in 4.0.
-     */
-    public function setEnhanceSigchildCompatibility($enhance)
-    {
-        @trigger_error(sprintf('The %s() method is deprecated since version 3.3 and will be removed in 4.0. Sigchild compatibility will always be enabled.', __METHOD__), E_USER_DEPRECATED);
-
-        $this->enhanceSigchildCompatibility = (bool) $enhance;
-
-        return $this;
-    }
-
     /**
      * Sets whether environment variables will be inherited or not.
      *
@@ -1322,7 +1268,7 @@ protected function updateStatus($blocking)
 
         $this->readPipes($running && $blocking, '\\' !== DIRECTORY_SEPARATOR || !$running);
 
-        if ($this->fallbackStatus && $this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
+        if ($this->fallbackStatus && $this->isSigchildEnabled()) {
             $this->processInformation = $this->fallbackStatus + $this->processInformation;
         }
 
@@ -1431,7 +1377,7 @@ private function close()
             if ($this->processInformation['signaled'] && 0 < $this->processInformation['termsig']) {
                 // if process has been signaled, no exitcode but a valid termsig, apply Unix convention
                 $this->exitcode = 128 + $this->processInformation['termsig'];
-            } elseif ($this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
+            } elseif ($this->isSigchildEnabled()) {
                 $this->processInformation['signaled'] = true;
                 $this->processInformation['termsig'] = -1;
             }
@@ -1496,7 +1442,7 @@ private function doSignal($signal, $throwException)
                 return false;
             }
         } else {
-            if (!$this->enhanceSigchildCompatibility || !$this->isSigchildEnabled()) {
+            if (!$this->isSigchildEnabled()) {
                 $ok = @proc_terminate($this->process, $signal);
             } elseif (function_exists('posix_kill')) {
                 $ok = @posix_kill($pid, $signal);
diff --git a/src/Symfony/Component/Process/Tests/ProcessTest.php b/src/Symfony/Component/Process/Tests/ProcessTest.php
index 9b74196c70aed..cab6595474859 100644
--- a/src/Symfony/Component/Process/Tests/ProcessTest.php
+++ b/src/Symfony/Component/Process/Tests/ProcessTest.php
@@ -28,7 +28,6 @@ class ProcessTest extends TestCase
     private static $phpBin;
     private static $process;
     private static $sigchild;
-    private static $notEnhancedSigchild = false;
 
     public static function setUpBeforeClass()
     {
@@ -420,7 +419,6 @@ public function testExitCodeCommandFailed()
         if ('\\' === DIRECTORY_SEPARATOR) {
             $this->markTestSkipped('Windows does not support POSIX exit code');
         }
-        $this->skipIfNotEnhancedSigchild();
 
         // such command run in bash return an exitcode 127
         $process = $this->getProcess('nonexistingcommandIhopeneversomeonewouldnameacommandlikethis');
@@ -455,7 +453,6 @@ public function testTTYCommandExitCode()
         if ('\\' === DIRECTORY_SEPARATOR) {
             $this->markTestSkipped('Windows does have /dev/tty support');
         }
-        $this->skipIfNotEnhancedSigchild();
 
         $process = $this->getProcess('echo "foo" >> /dev/null');
         $process->setTty(true);
@@ -481,8 +478,6 @@ public function testTTYInWindowsEnvironment()
 
     public function testExitCodeTextIsNullWhenExitCodeIsNull()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcess('');
         $this->assertNull($process->getExitCodeText());
     }
@@ -503,8 +498,6 @@ public function testPTYCommand()
 
     public function testMustRun()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcess('echo foo');
 
         $this->assertSame($process, $process->mustRun());
@@ -513,8 +506,6 @@ public function testMustRun()
 
     public function testSuccessfulMustRunHasCorrectExitCode()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcess('echo foo')->mustRun();
         $this->assertEquals(0, $process->getExitCode());
     }
@@ -524,16 +515,12 @@ public function testSuccessfulMustRunHasCorrectExitCode()
      */
     public function testMustRunThrowsException()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcess('exit 1');
         $process->mustRun();
     }
 
     public function testExitCodeText()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcess('');
         $r = new \ReflectionObject($process);
         $p = $r->getProperty('exitcode');
@@ -562,8 +549,6 @@ public function testUpdateStatus()
 
     public function testGetExitCodeIsNullOnStart()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcessForCode('usleep(100000);');
         $this->assertNull($process->getExitCode());
         $process->start();
@@ -574,8 +559,6 @@ public function testGetExitCodeIsNullOnStart()
 
     public function testGetExitCodeIsNullOnWhenStartingAgain()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcessForCode('usleep(100000);');
         $process->run();
         $this->assertEquals(0, $process->getExitCode());
@@ -587,8 +570,6 @@ public function testGetExitCodeIsNullOnWhenStartingAgain()
 
     public function testGetExitCode()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcess('echo foo');
         $process->run();
         $this->assertSame(0, $process->getExitCode());
@@ -624,8 +605,6 @@ public function testStop()
 
     public function testIsSuccessful()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcess('echo foo');
         $process->run();
         $this->assertTrue($process->isSuccessful());
@@ -633,8 +612,6 @@ public function testIsSuccessful()
 
     public function testIsSuccessfulOnlyAfterTerminated()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcessForCode('usleep(100000);');
         $process->start();
 
@@ -647,8 +624,6 @@ public function testIsSuccessfulOnlyAfterTerminated()
 
     public function testIsNotSuccessful()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcessForCode('throw new \Exception(\'BOUM\');');
         $process->run();
         $this->assertFalse($process->isSuccessful());
@@ -659,7 +634,6 @@ public function testProcessIsNotSignaled()
         if ('\\' === DIRECTORY_SEPARATOR) {
             $this->markTestSkipped('Windows does not support POSIX signals');
         }
-        $this->skipIfNotEnhancedSigchild();
 
         $process = $this->getProcess('echo foo');
         $process->run();
@@ -671,7 +645,6 @@ public function testProcessWithoutTermSignal()
         if ('\\' === DIRECTORY_SEPARATOR) {
             $this->markTestSkipped('Windows does not support POSIX signals');
         }
-        $this->skipIfNotEnhancedSigchild();
 
         $process = $this->getProcess('echo foo');
         $process->run();
@@ -683,7 +656,6 @@ public function testProcessIsSignaledIfStopped()
         if ('\\' === DIRECTORY_SEPARATOR) {
             $this->markTestSkipped('Windows does not support POSIX signals');
         }
-        $this->skipIfNotEnhancedSigchild();
 
         $process = $this->getProcessForCode('sleep(32);');
         $process->start();
@@ -701,7 +673,10 @@ public function testProcessThrowsExceptionWhenExternallySignaled()
         if (!function_exists('posix_kill')) {
             $this->markTestSkipped('Function posix_kill is required.');
         }
-        $this->skipIfNotEnhancedSigchild(false);
+
+        if (self::$sigchild) {
+            $this->markTestSkipped('PHP is compiled with --enable-sigchild.');
+        }
 
         $process = $this->getProcessForCode('sleep(32.1);');
         $process->start();
@@ -912,8 +887,6 @@ public function testSignal()
      */
     public function testExitCodeIsAvailableAfterSignal()
     {
-        $this->skipIfNotEnhancedSigchild();
-
         $process = $this->getProcess('sleep 4');
         $process->start();
         $process->signal(SIGKILL);
@@ -1487,21 +1460,6 @@ private function getProcess($commandline, $cwd = null, array $env = null, $input
         $process = new Process($commandline, $cwd, $env, $input, $timeout);
         $process->inheritEnvironmentVariables();
 
-        if (false !== $enhance = getenv('ENHANCE_SIGCHLD')) {
-            try {
-                $process->setEnhanceSigchildCompatibility(false);
-                $process->getExitCode();
-                $this->fail('ENHANCE_SIGCHLD must be used together with a sigchild-enabled PHP.');
-            } catch (RuntimeException $e) {
-                $this->assertSame('This PHP has been compiled with --enable-sigchild. You must use setEnhanceSigchildCompatibility() to use this method.', $e->getMessage());
-                if ($enhance) {
-                    $process->setEnhanceSigchildCompatibility(true);
-                } else {
-                    self::$notEnhancedSigchild = true;
-                }
-            }
-        }
-
         if (self::$process) {
             self::$process->stop(0);
         }
@@ -1516,22 +1474,6 @@ private function getProcessForCode($code, $cwd = null, array $env = null, $input
     {
         return $this->getProcess(array(self::$phpBin, '-r', $code), $cwd, $env, $input, $timeout);
     }
-
-    private function skipIfNotEnhancedSigchild($expectException = true)
-    {
-        if (self::$sigchild) {
-            if (!$expectException) {
-                $this->markTestSkipped('PHP is compiled with --enable-sigchild.');
-            } elseif (self::$notEnhancedSigchild) {
-                if (method_exists($this, 'expectException')) {
-                    $this->expectException('Symfony\Component\Process\Exception\RuntimeException');
-                    $this->expectExceptionMessage('This PHP has been compiled with --enable-sigchild.');
-                } else {
-                    $this->setExpectedException('Symfony\Component\Process\Exception\RuntimeException', 'This PHP has been compiled with --enable-sigchild.');
-                }
-            }
-        }
-    }
 }
 
 class NonStringifiable