diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..9b2611d
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,43 @@
+language: php
+
+dist: trusty
+root: false
+
+env:
+  global:
+    - setup=stable
+
+cache:
+  directories:
+    - $HOME/.composer/cache
+
+matrix:
+  fast_finish: true
+  allow_failures:
+    - php: hhvm
+  include:
+    - php: 5.6
+    - php: 5.6
+      env: setup=lowest
+    - php: 7.0
+    - php: 7.0
+      env: setup=lowest
+    - php: 7.1
+    - php: 7.1
+      env: setup=lowest
+    - php: 7.2
+    - php: 7.2
+      env: setup=lowest
+    - php: hhvm
+    - php: hhvm
+      env: setup=lowest
+
+before_install:
+  - travis_retry composer self-update
+  - travis_retry composer config -g github-oauth.github.com "$GITHUB_TOKEN"
+
+install:
+  - if [[ $setup = 'stable' ]]; then travis_retry composer update --prefer-dist --no-interaction --prefer-stable --no-suggest; fi
+  - if [[ $setup = 'lowest' ]]; then travis_retry composer update --prefer-dist --no-interaction --prefer-lowest --prefer-stable --no-suggest; fi
+
+script: composer run test
diff --git a/README.md b/README.md
index 41982bc..b1ac001 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,7 @@
+[![Build Status](https://travis-ci.org/slowprog/CopyFile.svg?branch=master)](https://travis-ci.org/slowprog/CopyFile)
+[![Latest Stable Version](https://poser.pugx.org/slowprog/composer-copy-file/version)](https://packagist.org/packages/slowprog/composer-copy-file)
+[![Total Downloads](https://poser.pugx.org/slowprog/composer-copy-file/downloads)](https://packagist.org/packages/slowprog/composer-copy-file)
+
 # Composer copy file
 
 Composer script copying your files after install. Supports copying of entire directories, individual files and complex nested directories.
@@ -26,10 +30,39 @@ For example copy fonts:
 }
 ```
 
+In a development you may use `-dev` suffix. For example copy non-minified in development and minified in production:
+
+```
+{
+    "require":{
+        "twbs/bootstrap": "~3.3",
+        "slowprog/composer-copy-file": "~0.2"
+    },
+    "scripts": {
+        "post-install-cmd": [
+            "SlowProg\\CopyFile\\ScriptHandler::copy"
+        ],
+        "post-update-cmd": [
+            "SlowProg\\CopyFile\\ScriptHandler::copy"
+        ]
+    },
+    "extra": {
+        "copy-file": {
+            "vendor/twbs/bootstrap/dist/js/bootstrap.min.js": "web/js/bootstrap.js"
+        },
+        "copy-file-dev": {
+            "vendor/twbs/bootstrap/dist/js/bootstrap.js": "web/js/bootstrap.js"
+        }
+    }
+}
+```
+
 ## Use cases
 
 You need to be careful when using a last slash. The file-destination is different from the directory-destination with the slash.
 
+If in destination directory already exists copy of file, then it will be override. To overwrite only older files append `?` in end of destination path.
+
 Source directory hierarchy:
 
 ```
@@ -104,3 +137,33 @@ dir/
             file1.txt
             file_rename.txt
     ```
+
+4. Override only older files:
+
+    ```
+    {
+        "extra": {
+            "copy-file": {
+                "dir/subdir/": "web/other/?"
+            }
+        }
+    }
+    ```
+    
+    Preset:
+    
+    ```
+    web/
+        other/
+            file1.txt - Recently modified
+            file2.txt - Old rotten file
+    ```
+    
+    Result:
+
+    ```
+    web/
+        other/
+            file1.txt - Not changed
+            file2.txt - Replaced
+    ```
\ No newline at end of file
diff --git a/ScriptHandler.php b/ScriptHandler.php
index 3091245..5f9d8aa 100644
--- a/ScriptHandler.php
+++ b/ScriptHandler.php
@@ -15,12 +15,13 @@ class ScriptHandler
     public static function copy(Event $event)
     {
         $extras = $event->getComposer()->getPackage()->getExtra();
+        $extraField = $event->isDevMode() && isset($extras['copy-file-dev']) ? 'copy-file-dev' : 'copy-file';
 
-        if (!isset($extras['copy-file'])) {
+        if (!isset($extras[$extraField])) {
             throw new \InvalidArgumentException('The dirs or files needs to be configured through the extra.copy-file setting.');
         }
 
-        $files = $extras['copy-file'];
+        $files = $extras[$extraField];
 
         if ($files === array_values($files)) {
             throw new \InvalidArgumentException('The extra.copy-file must be hash like "{<dir_or_file_from>: <dir_to>}".');
@@ -30,6 +31,12 @@ public static function copy(Event $event)
         $io = $event->getIO();
 
         foreach ($files as $from => $to) {
+            // check the overwrite newer files disable flag (? in end of path)
+            $overwriteNewerFiles = substr($to, -1) != '?';
+            if (!$overwriteNewerFiles) {
+                $to = substr($to, 0, -1);
+            }
+            
             // Check the renaming of file for direct moving (file-to-file)
             $isRenameFile = substr($to, -1) != '/' && !is_dir($from);
 
@@ -59,7 +66,7 @@ public static function copy(Event $event)
                     $dest = sprintf('%s/%s', $to, $file->getRelativePathname());
 
                     try {
-                        $fs->copy($file, $dest);
+                        $fs->copy($file, $dest, $overwriteNewerFiles);
                     } catch (IOException $e) {
                         throw new \InvalidArgumentException(sprintf('<error>Could not copy %s</error>', $file->getBaseName()), $e->getCode(), $e);
                     }
@@ -67,9 +74,9 @@ public static function copy(Event $event)
             } else {
                 try {
                     if ($isRenameFile) {
-                        $fs->copy($from, $to);
+                        $fs->copy($from, $to, $overwriteNewerFiles);
                     } else {
-                        $fs->copy($from, $to.'/'.basename($from));
+                        $fs->copy($from, $to.'/'.basename($from), $overwriteNewerFiles);
                     }
                 } catch (IOException $e) {
                     throw new \InvalidArgumentException(sprintf('<error>Could not copy %s</error>', $from), $e->getCode(), $e);
diff --git a/composer.json b/composer.json
index 3121f28..52b0bb7 100644
--- a/composer.json
+++ b/composer.json
@@ -11,16 +11,23 @@
         }
     ],
     "require": {
-        "php": ">=5.3.3"
+        "php": ">=5.6"
     },
     "require-dev": {
         "composer/composer": "1.0.*@dev",
         "symfony/filesystem": "~2.7",
         "symfony/finder": "~2.7",
-        "phpunit/phpunit": "~5.0",
-        "mikey179/vfsStream": "~1"
+        "phpunit/phpunit": "5.7.27",
+        "mikey179/vfsStream": "~1",
+        "php-mock/php-mock-phpunit": "~1"
     },
     "autoload": {
         "psr-4": { "SlowProg\\CopyFile\\": "" }
+    },
+    "autoload-dev": {
+        "classmap": [ "tests/" ]
+    },
+    "scripts": {
+        "test": "phpunit --verbose"
     }
 }
diff --git a/phpunit.xml b/phpunit.xml
index 9f720ad..4bb4964 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -12,7 +12,7 @@
          syntaxCheck="false">
     <testsuites>
         <testsuite name="CopyFile Test Suite">
-            <directory suffix=".php">./tests/</directory>
+            <directory suffix="Test.php">./tests/</directory>
         </testsuite>
     </testsuites>
 </phpunit>
diff --git a/tests/CopyFileTest.php b/tests/CopyFileTest.php
index 4b212f7..7102a87 100644
--- a/tests/CopyFileTest.php
+++ b/tests/CopyFileTest.php
@@ -1,64 +1,51 @@
 <?php
 
-use SlowProg\CopyFile\ScriptHandler;
+use \SlowProg\CopyFile\ScriptHandler;
+use \org\bovigo\vfs\vfsStream;
 
-use org\bovigo\vfs\vfsStream;
-use Composer\IO\IOInterface;
-
-class CopyFileTest extends PHPUnit_Framework_TestCase
+class CopyFileTest extends TestCase
 {
-    public function setUp()
-    {
-
-    }
+    use \phpmock\phpunit\PHPMock;
 
     public function testFilesystem()
     {
-        $root = $this->getFilesystem();
-
-        $this->assertTrue($root->hasChild('from/file1'));
-        $this->assertTrue($root->hasChild('from/file2'));
+        $this->assertTrue($this->root->hasChild('from/file1'));
+        $this->assertTrue($this->root->hasChild('from/file2'));
 
-        $this->assertTrue($root->hasChild('file3'));
+        $this->assertTrue($this->root->hasChild('file3'));
 
-        $this->assertTrue($root->hasChild('from_complex/file4'));
-        $this->assertTrue($root->hasChild('from_complex/sub_dir/file5'));
+        $this->assertTrue($this->root->hasChild('from_complex/file4'));
+        $this->assertTrue($this->root->hasChild('from_complex/sub_dir/file5'));
     }
 
     public function testCopyDirToDir()
     {
-        $root = $this->getFilesystem();
-
-        $this->assertFalse($root->hasChild('to/file1'));
-        $this->assertFalse($root->hasChild('to/file2'));
+        $this->assertFalse($this->root->hasChild('to/file1'));
+        $this->assertFalse($this->root->hasChild('to/file2'));
 
         ScriptHandler::copy($this->getEventMock([
             vfsStream::url('root/from')=> vfsStream::url('root/to')
         ]));
 
-        $this->assertTrue($root->hasChild('to/file1'));
-        $this->assertTrue($root->hasChild('to/file2'));
+        $this->assertTrue($this->root->hasChild('to/file1'));
+        $this->assertTrue($this->root->hasChild('to/file2'));
     }
 
     public function testCopyDirToNotExistsDir()
     {
-        $root = $this->getFilesystem();
-
-        $this->assertFalse($root->hasChild('not_exists'));
+        $this->assertFalse($this->root->hasChild('not_exists'));
 
         ScriptHandler::copy($this->getEventMock([
             vfsStream::url('root/from')=> vfsStream::url('root/not_exists')
         ]));
 
-        $this->assertTrue($root->hasChild('not_exists'));
-        $this->assertTrue($root->hasChild('not_exists/file1'));
-        $this->assertTrue($root->hasChild('not_exists/file2'));
+        $this->assertTrue($this->root->hasChild('not_exists'));
+        $this->assertTrue($this->root->hasChild('not_exists/file1'));
+        $this->assertTrue($this->root->hasChild('not_exists/file2'));
     }
 
     public function testCopyFromNotExistsDir()
     {
-        $root = $this->getFilesystem();
-
         $this->expectException(InvalidArgumentException::class);
 
         ScriptHandler::copy($this->getEventMock([
@@ -68,8 +55,6 @@ public function testCopyFromNotExistsDir()
 
     public function testCopyDirToFile()
     {
-        $root = $this->getFilesystem();
-
         $this->expectException(InvalidArgumentException::class);
 
         ScriptHandler::copy($this->getEventMock([
@@ -79,144 +64,74 @@ public function testCopyDirToFile()
 
     public function testCopyFileToDir()
     {
-        $root = $this->getFilesystem();
-
-        $this->assertFalse($root->hasChild('to/file3'));
+        $this->assertFalse($this->root->hasChild('to/file3'));
 
         ScriptHandler::copy($this->getEventMock([
             vfsStream::url('root/file3')=> vfsStream::url('root/to/')
         ]));
 
-        $this->assertTrue($root->hasChild('to/file3'));
+        $this->assertTrue($this->root->hasChild('to/file3'));
     }
 
     public function testCopyFileToFile()
     {
-        $root = $this->getFilesystem();
-
-        $this->assertFalse($root->hasChild('to/file_new'));
+        $this->assertFalse($this->root->hasChild('to/file_new'));
 
         ScriptHandler::copy($this->getEventMock([
             vfsStream::url('root/file3')=> vfsStream::url('root/to/file_new')
         ]));
 
-        $this->assertTrue($root->hasChild('to/file_new'));
+        $this->assertTrue($this->root->hasChild('to/file_new'));
     }
 
     public function testCopyFromComplexDir()
     {
-        $root = $this->getFilesystem();
-
-        $this->assertFalse($root->hasChild('to/file4'));
-        $this->assertFalse($root->hasChild('to/sub_dir/file5'));
-        $this->assertFalse($root->hasChild('to/git_keep_dir'));
+        $this->assertFalse($this->root->hasChild('to/file4'));
+        $this->assertFalse($this->root->hasChild('to/sub_dir/file5'));
+        $this->assertFalse($this->root->hasChild('to/git_keep_dir'));
 
         ScriptHandler::copy($this->getEventMock([
             vfsStream::url('root/from_complex')=> vfsStream::url('root/to')
         ]));
 
-        $this->assertTrue($root->hasChild('to/file4'));
-        $this->assertTrue($root->hasChild('to/sub_dir/file5'));
-        $this->assertTrue($root->hasChild('to/git_keep_dir'));
+        $this->assertTrue($this->root->hasChild('to/file4'));
+        $this->assertTrue($this->root->hasChild('to/sub_dir/file5'));
+        $this->assertTrue($this->root->hasChild('to/git_keep_dir'));
     }
 
-    public function testConfigError()
+    public function testRewriteExists()
     {
-        $root = $this->getFilesystem();
+        $this->root->lastModified(0);
+        $this->root->getChild('dynamic_dir/file1')->lastModified(1);
 
-        $this->expectException(InvalidArgumentException::class);
+        $exchanged = vfsStream::url('root/dynamic_dir/file1');
+        $unaltered = vfsStream::url('root/dynamic_dir/file2');
 
-        ScriptHandler::copy($this->getEventMock([]));
-        ScriptHandler::copy($this->getEventMock(['to', 'from', 'file3']));
-        ScriptHandler::copy($this->getEventMock(null));
-        ScriptHandler::copy($this->getEventMock('some string'));
-    }
+        // allow filemtime check apply for vfs protocol
+        $this->getFunctionMock('Symfony\Component\Filesystem', 'parse_url')
+            ->expects($this->any())->willReturn(null);
 
-    /**
-     * @return \PHPUnit_Framework_MockObject_MockObject
-     */
-    private function getEventMock($copyFileConfig)
-    {
-        $event = $this->getMockBuilder('Composer\Script\Event')
-            ->disableOriginalConstructor()
-            ->getMock();
+        // preset filemtime check
+        $this->getFunctionMock('Symfony\Component\Filesystem', 'filemtime')
+            ->expects($this->any())->willReturnCallback(function ($filename) use ($unaltered) {
+                return $filename === $unaltered ? 1 : 2;
+            });
 
-        $event
-            ->expects($this->once())
-            ->method('getComposer')
-            ->will($this->returnValue($this->getComposerMock($copyFileConfig)));
+        ScriptHandler::copy($this->getEventMock(array(
+            vfsStream::url('root/from') => vfsStream::url('root/dynamic_dir') . '?'
+        )));
 
-        $event
-            ->method('getIO')
-            ->will($this->returnValue($this->createMock('\Composer\IO\IOInterface')));
-
-        return $event;
-    }
-
-    /**
-     * @return \PHPUnit_Framework_MockObject_MockObject
-     */
-    private function getComposerMock($copyFileConfig)
-    {
-        $package = $this->getPackageMock($copyFileConfig);
-
-        $composer = $this->getMockBuilder('Composer\Composer')
-            ->disableOriginalConstructor()
-            ->getMock();
-
-        $composer
-            ->expects($this->once())
-            ->method('getPackage')
-            ->will($this->returnValue($package));
-
-        return $composer;
+        $this->assertFileNotEquals(vfsStream::url('root/from/file1'), $exchanged);
+        $this->assertFileEquals(vfsStream::url('root/from/file2'), $unaltered);
     }
 
-    /**
-     * @return \PHPUnit_Framework_MockObject_MockObject
-     */
-    private function getPackageMock($copyFileConfig)
+    public function testConfigError()
     {
-        $extra = null;
-
-        if (!is_null($copyFileConfig)) {
-            $extra = [
-                'copy-file' => $copyFileConfig,
-            ];
-        }
-
-        $package = $this->getMockBuilder('Composer\Package\RootPackageInterface')
-            ->disableOriginalConstructor()
-            ->getMock();
-
-        $package
-            ->expects($this->once())
-            ->method('getExtra')
-            ->will($this->returnValue($extra));
-
-        return $package;
-    }
+        $this->expectException(InvalidArgumentException::class);
 
-    private function getFilesystem()
-    {
-        $structure = [
-            'from' => [
-                'file1' => 'Some content',
-                'file2' => 'Some content',
-            ],
-            'to' => [],
-            'file3' => 'Some content',
-            'from_complex' => [
-                'file4' => 'Some content',
-                'sub_dir' => [
-                    'file5' => 'Some content',
-                ],
-                'git_keep_dir' => [
-                    '.gitkeep' => '',
-                ],
-            ],
-        ];
-
-        return vfsStream::setup('root', null, $structure);
+        ScriptHandler::copy($this->getEventMock([]));
+        ScriptHandler::copy($this->getEventMock(['to', 'from', 'file3']));
+        ScriptHandler::copy($this->getEventMock(null));
+        ScriptHandler::copy($this->getEventMock('some string'));
     }
 }
diff --git a/tests/TestCase.php b/tests/TestCase.php
new file mode 100644
index 0000000..d92f7f6
--- /dev/null
+++ b/tests/TestCase.php
@@ -0,0 +1,114 @@
+<?php
+
+use \org\bovigo\vfs\vfsStream;
+
+abstract class TestCase extends PHPUnit_Framework_TestCase
+{
+    /**
+     * @var \org\bovigo\vfs\vfsStreamDirectory
+     */
+    protected $root;
+
+    public function setUp()
+    {
+        $this->root = $this->getFilesystem();
+    }
+
+    /**
+     * @param array|string|null $copyFileConfig
+     * @return \PHPUnit_Framework_MockObject_MockObject|\Composer\Script\Event
+     */
+    protected function getEventMock($copyFileConfig)
+    {
+        $event = $this->getMockBuilder('\Composer\Script\Event')
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $event
+            ->expects($this->once())
+            ->method('getComposer')
+            ->will($this->returnValue($this->getComposerMock($copyFileConfig)));
+
+        $event
+            ->method('getIO')
+            ->will($this->returnValue($this->createMock('\Composer\IO\IOInterface')));
+
+        return $event;
+    }
+
+    /**
+     * @param array|string|null $copyFileConfig
+     * @return \PHPUnit_Framework_MockObject_MockObject|\Composer\Composer
+     */
+    protected function getComposerMock($copyFileConfig)
+    {
+        $package = $this->getPackageMock($copyFileConfig);
+
+        $composer = $this->getMockBuilder('\Composer\Composer')
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $composer
+            ->expects($this->once())
+            ->method('getPackage')
+            ->will($this->returnValue($package));
+
+        return $composer;
+    }
+
+    /**
+     * @param array|string|null $copyFileConfig
+     * @return \PHPUnit_Framework_MockObject_MockObject|\Composer\Package\RootPackageInterface
+     */
+    protected function getPackageMock($copyFileConfig)
+    {
+        $extra = null;
+
+        if (!is_null($copyFileConfig)) {
+            $extra = array(
+                'copy-file' => $copyFileConfig,
+            );
+        }
+
+        $package = $this->getMockBuilder('\Composer\Package\RootPackageInterface')
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $package
+            ->expects($this->once())
+            ->method('getExtra')
+            ->will($this->returnValue($extra));
+
+        return $package;
+    }
+
+    /**
+     * @return \org\bovigo\vfs\vfsStreamDirectory
+     */
+    protected function getFilesystem()
+    {
+        $structure = array(
+            'from' => array(
+                'file1' => 'Some content',
+                'file2' => 'Some content',
+            ),
+            'to' => array(),
+            'file3' => 'Some content',
+            'from_complex' => array(
+                'file4' => 'Some content',
+                'sub_dir' => array(
+                    'file5' => 'Some content',
+                ),
+                'git_keep_dir' => array(
+                    '.gitkeep' => '',
+                ),
+            ),
+            'dynamic_dir' => array(
+                'file1' => 'Exchanged content',
+                'file2' => 'Unaltered content',
+            ),
+        );
+
+        return vfsStream::setup('root', null, $structure);
+    }
+}
\ No newline at end of file