diff --git a/.travis.yml b/.travis.yml
index 5b5b855..55c7d7d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,9 @@
 language: php
 php:
   - 7.1
+  - 7.2
+  - 7.3
+  - 7.4
 
 before_script:
   - composer install --prefer-dist
diff --git a/composer.json b/composer.json
index ec1ab92..4d6d96a 100644
--- a/composer.json
+++ b/composer.json
@@ -15,8 +15,8 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "4.0.*",
-        "squizlabs/php_codesniffer": "1.5.5"
+        "phpunit/phpunit": "7.0.*",
+        "squizlabs/php_codesniffer": "3.5.*"
     },
     "require": {
         "php": ">=7.1"
diff --git a/src/RateAdapter.php b/src/RateAdapter.php
index 6ed0a6f..d15d117 100644
--- a/src/RateAdapter.php
+++ b/src/RateAdapter.php
@@ -95,6 +95,8 @@ abstract class RateAdapter
 
     protected function sortByCost()
     {
-        uasort($this->rates, create_function('$a, $b', 'return ($a->getCost() > $b->getCost());'));
+        uasort($this->rates, function ($a, $b) {
+            return ($a->getCost() > $b->getCost());
+        });
     }
 }
diff --git a/src/Ship.php b/src/Ship.php
index 0ce4c50..3ccdbff 100644
--- a/src/Ship.php
+++ b/src/Ship.php
@@ -139,8 +139,10 @@ class Ship
         return $display_rates;
     }
 
-    protected function sortByCost(& $rates)
+    protected function sortByCost(&$rates)
     {
-        uasort($rates, create_function('$a, $b', 'return ($a->getCost() > $b->getCost());'));
+        uasort($rates, function ($a, $b) {
+            return ($a->getCost() > $b->getCost());
+        });
     }
 }
diff --git a/src/UPS/Rate.php b/src/UPS/Rate.php
index 8957021..13695cd 100644
--- a/src/UPS/Rate.php
+++ b/src/UPS/Rate.php
@@ -95,8 +95,8 @@ class Rate extends RateAdapter
         ]);
 
         $this->setRequestAdapter(Arr::get($options, 'requestAdapter', new RateRequest\Post()));
-
     }
+
     protected function validate()
     {
         $this->validatePackages();
diff --git a/tests/ArrTest.php b/tests/ArrTest.php
index 706f4c9..cfc7291 100644
--- a/tests/ArrTest.php
+++ b/tests/ArrTest.php
@@ -1,7 +1,9 @@
 <?php
 namespace pdt256\Shipping;
 
-class ArrTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class ArrTest extends TestCase
 {
     public function providerGet()
     {
diff --git a/tests/Fedex/FedexTest.php b/tests/Fedex/FedexTest.php
index e7d09d3..418283c 100644
--- a/tests/Fedex/FedexTest.php
+++ b/tests/Fedex/FedexTest.php
@@ -7,8 +7,9 @@ use pdt256\Shipping\Package;
 use pdt256\Shipping\Shipment;
 use pdt256\Shipping\Quote;
 use DateTime;
+use PHPUnit\Framework\TestCase;
 
-class RateTest extends \PHPUnit_Framework_TestCase
+class RateTest extends TestCase
 {
     /** @var Shipment */
     protected $shipment;
@@ -182,6 +183,5 @@ class RateTest extends \PHPUnit_Framework_TestCase
             'requestAdapter' => new StubFedex,
         ]);
         $rateAdapter->getRates();
-
     }
 }
diff --git a/tests/PackageDimensionsTest.php b/tests/PackageDimensionsTest.php
index a6451fe..155548a 100644
--- a/tests/PackageDimensionsTest.php
+++ b/tests/PackageDimensionsTest.php
@@ -5,8 +5,9 @@ namespace pdt256\Shipping;
 use pdt256\Shipping\RateRequest\StubFedex;
 use pdt256\Shipping\RateRequest\StubUPS;
 use pdt256\Shipping\RateRequest\StubUSPS;
+use PHPUnit\Framework\TestCase;
 
-class PackageDimensionsValidationTrait extends \PHPUnit_Framework_TestCase
+class PackageDimensionsValidationTrait extends TestCase
 {
     protected function getNormalPackage()
     {
diff --git a/tests/PackageTest.php b/tests/PackageTest.php
index 2407da6..4da2d6b 100644
--- a/tests/PackageTest.php
+++ b/tests/PackageTest.php
@@ -1,7 +1,9 @@
 <?php
 namespace pdt256\Shipping;
 
-class PackageTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class PackageTest extends TestCase
 {
     public function testCreate()
     {
diff --git a/tests/QuoteTest.php b/tests/QuoteTest.php
index 34405f5..4f157c4 100644
--- a/tests/QuoteTest.php
+++ b/tests/QuoteTest.php
@@ -2,8 +2,9 @@
 namespace pdt256\Shipping;
 
 use DateTime;
+use PHPUnit\Framework\TestCase;
 
-class QuoteTest extends \PHPUnit_Framework_TestCase
+class QuoteTest extends TestCase
 {
     public function testCreate()
     {
diff --git a/tests/RateAdapterTest.php b/tests/RateAdapterTest.php
index c7f351f..b33ec30 100644
--- a/tests/RateAdapterTest.php
+++ b/tests/RateAdapterTest.php
@@ -1,7 +1,9 @@
 <?php
 namespace pdt256\Shipping;
 
-class RateAdapterTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class RateAdapterTest extends TestCase
 {
     public function testCreate()
     {
diff --git a/tests/ShipTest.php b/tests/ShipTest.php
index 94175b3..fb9c58b 100644
--- a/tests/ShipTest.php
+++ b/tests/ShipTest.php
@@ -2,8 +2,9 @@
 namespace pdt256\Shipping;
 
 use DateTime;
+use PHPUnit\Framework\TestCase;
 
-class ShipTest extends \PHPUnit_Framework_TestCase
+class ShipTest extends TestCase
 {
     /** @var Shipment */
     public $shipment;
diff --git a/tests/ShipmentTest.php b/tests/ShipmentTest.php
index 13af702..02cc92e 100644
--- a/tests/ShipmentTest.php
+++ b/tests/ShipmentTest.php
@@ -1,7 +1,9 @@
 <?php
 namespace pdt256\Shipping;
 
-class ShipmentTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class ShipmentTest extends TestCase
 {
     public function testCreate()
     {
diff --git a/tests/UPS/RateTest.php b/tests/UPS/RateTest.php
index c51bb5d..d8aa75f 100644
--- a/tests/UPS/RateTest.php
+++ b/tests/UPS/RateTest.php
@@ -6,8 +6,9 @@ use pdt256\Shipping\Ship;
 use pdt256\Shipping\Package;
 use pdt256\Shipping\Shipment;
 use pdt256\Shipping\Quote;
+use PHPUnit\Framework\TestCase;
 
-class RateTest extends \PHPUnit_Framework_TestCase
+class RateTest extends TestCase
 {
     /** @var Shipment */
     protected $shipment;
diff --git a/tests/USPS/RateTest.php b/tests/USPS/RateTest.php
index b88897f..3225343 100644
--- a/tests/USPS/RateTest.php
+++ b/tests/USPS/RateTest.php
@@ -6,8 +6,9 @@ use pdt256\Shipping\Ship;
 use pdt256\Shipping\Package;
 use pdt256\Shipping\Shipment;
 use pdt256\Shipping\Quote;
+use PHPUnit\Framework\TestCase;
 
-class RateTest extends \PHPUnit_Framework_TestCase
+class RateTest extends TestCase
 {
     /** @var Shipment */
     protected $shipment;
diff --git a/tests/ValidatorTest.php b/tests/ValidatorTest.php
index 1e926ae..e148c91 100644
--- a/tests/ValidatorTest.php
+++ b/tests/ValidatorTest.php
@@ -1,7 +1,9 @@
 <?php
 namespace pdt256\Shipping;
 
-class ValidatorTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class ValidatorTest extends TestCase
 {
     /**
      * @expectedException \LogicException