diff --git a/.travis.yml b/.travis.yml
index 29fdc0c52..6c9221063 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,25 +13,21 @@ branches:
 
 env:
     global:
-        - MIN_PHP=5.5.9
+        - MIN_PHP=7.0
 
 matrix:
     fast_finish: true
     allow_failures:
-        - php: 5.5
+        - php: 7.0
           env: deps="low"
     include:
-        - php: 5.5
+        - php: 7.0
           env: deps="low"
-        - php: 5.5
-        - php: 5.6
         - php: 7.0
         - php: 7.1
-        - php: hhvm
 
 before_install:
-    - if [ "$TRAVIS_PHP_VERSION" != "hhvm" && "$TRAVIS_PHP_VERSION" != "7.0" ]; then pecl install geoip; fi
-    - if [ "$TRAVIS_PHP_VERSION" == "7.0" ]; then composer require "geoip/geoip"; fi
+    - composer require "geoip/geoip" --no-update
     - |
       # General configuration
       stty cols 120
@@ -56,12 +52,8 @@ before_install:
       COMPONENTS=$(find src -mindepth 2 -type f -name phpunit.xml.dist -printf '%h\n')
 
       # php.ini configuration
-      if [[ $PHP = hhvm* ]]; then
-          INI=/etc/hhvm/php.ini
-      else
-          INI=~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini
-          phpenv config-rm xdebug.ini || echo "xdebug not available"
-      fi
+      INI=~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini
+      phpenv config-rm xdebug.ini || echo "xdebug not available"
       echo memory_limit = -1 >> $INI
 
 install:
@@ -78,8 +70,6 @@ install:
             # Test the PhpUnit bridge on PHP 5.5, using the original phpunit script
             tfold src/Symfony/Bridge/PhpUnit \
             "cd src/Symfony/Bridge/PhpUnit && wget https://phar.phpunit.de/phpunit-4.8.phar && phpenv global 5.3 && composer update --no-progress --ansi && php phpunit-4.8.phar"
-        elif [[ $PHP = hhvm* ]]; then
-            $PHPUNIT --exclude-group benchmark,intl-data
         else
             echo "$COMPONENTS" | parallel --gnu "tfold {} $PHPUNIT_X {}"
             tfold tty-group $PHPUNIT --group tty
diff --git a/composer.json b/composer.json
index 9f54b9068..00fcd3191 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "igorw/get-in": "^1.0",
         "psr/http-message-implementation": "^1.0",
         "php-http/client-implementation": "^1.0",
@@ -21,15 +21,14 @@
         "php-http/discovery": "^1.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8 || ^5.4",
+        "phpunit/phpunit": "^6.1",
         "geocoder-php/provider-integration-tests": "dev-master",
-        "symfony/phpunit-bridge": "^3.2",
         "geoip2/geoip2": "~2.0",
         "symfony/stopwatch": "~2.5",
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "php-http/mock-client": "^1.0",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "suggest": {
         "ext-geoip": "Enabling the geoip extension allows you to use the MaxMindProvider.",
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 1f9eeb478..1023e7000 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -50,8 +50,4 @@
             </exclude>
         </whitelist>
     </filter>
-
-    <listeners>
-        <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener" />
-    </listeners>
 </phpunit>
diff --git a/src/Common/Tests/Dumper/GeoArrayTest.php b/src/Common/Tests/Dumper/GeoArrayTest.php
index f06921797..53efc4f1e 100644
--- a/src/Common/Tests/Dumper/GeoArrayTest.php
+++ b/src/Common/Tests/Dumper/GeoArrayTest.php
@@ -12,11 +12,12 @@
 
 use Geocoder\Dumper\GeoArray;
 use Geocoder\Model\LocationFactory;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author Tomas Norkūnas <norkunas.tom@gmail.com>
  */
-class GeoArrayTest extends \PHPUnit_Framework_TestCase
+class GeoArrayTest extends TestCase
 {
     /**
      * @var GeoArray
diff --git a/src/Common/Tests/Dumper/GeoJsonTest.php b/src/Common/Tests/Dumper/GeoJsonTest.php
index 8c7bc5b7c..7bca925ee 100644
--- a/src/Common/Tests/Dumper/GeoJsonTest.php
+++ b/src/Common/Tests/Dumper/GeoJsonTest.php
@@ -12,12 +12,13 @@
 
 use Geocoder\Dumper\GeoJson;
 use Geocoder\Model\LocationFactory;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author Jan Sorgalla <jsorgalla@googlemail.com>
  * @author William Durand <william.durand1@gmail.com>
  */
-class GeoJsonTest extends \PHPUnit_Framework_TestCase
+class GeoJsonTest extends TestCase
 {
     /**
      * @var GeoJson
diff --git a/src/Common/Tests/Dumper/GpxTest.php b/src/Common/Tests/Dumper/GpxTest.php
index a806b76b6..afea8cd48 100644
--- a/src/Common/Tests/Dumper/GpxTest.php
+++ b/src/Common/Tests/Dumper/GpxTest.php
@@ -13,11 +13,12 @@
 use Geocoder\Geocoder;
 use Geocoder\Dumper\Gpx;
 use Geocoder\Model\LocationFactory;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author William Durand <william.durand1@gmail.com>
  */
-class GpxTest extends \PHPUnit_Framework_TestCase
+class GpxTest extends TestCase
 {
     /**
      * @var Gpx
diff --git a/src/Common/Tests/Dumper/KmlTest.php b/src/Common/Tests/Dumper/KmlTest.php
index d4817e903..9794c7f2b 100644
--- a/src/Common/Tests/Dumper/KmlTest.php
+++ b/src/Common/Tests/Dumper/KmlTest.php
@@ -12,12 +12,13 @@
 
 use Geocoder\Dumper\Kml;
 use Geocoder\Model\LocationFactory;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author Jan Sorgalla <jsorgalla@googlemail.com>
  * @author William Durand <william.durand1@gmail.com>
  */
-class KmlTest extends \PHPUnit_Framework_TestCase
+class KmlTest extends TestCase
 {
     /**
      * @var Kml
diff --git a/src/Common/Tests/Dumper/WkbTest.php b/src/Common/Tests/Dumper/WkbTest.php
index e7cc48e28..065721273 100644
--- a/src/Common/Tests/Dumper/WkbTest.php
+++ b/src/Common/Tests/Dumper/WkbTest.php
@@ -12,12 +12,13 @@
 
 use Geocoder\Dumper\Wkb;
 use Geocoder\Model\LocationFactory;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author Jan Sorgalla <jsorgalla@googlemail.com>
  * @author William Durand <william.durand1@gmail.com>
  */
-class WkbTest extends \PHPUnit_Framework_TestCase
+class WkbTest extends TestCase
 {
     /**
      * @var Wkb
diff --git a/src/Common/Tests/Dumper/WktTest.php b/src/Common/Tests/Dumper/WktTest.php
index 3eb86e81c..8a960fd53 100644
--- a/src/Common/Tests/Dumper/WktTest.php
+++ b/src/Common/Tests/Dumper/WktTest.php
@@ -12,12 +12,13 @@
 
 use Geocoder\Dumper\Wkt;
 use Geocoder\Model\LocationFactory;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author Jan Sorgalla <jsorgalla@googlemail.com>
  * @author William Durand <william.durand1@gmail.com>
  */
-class WktTest extends \PHPUnit_Framework_TestCase
+class WktTest extends TestCase
 {
     /**
      * @var Wkt
diff --git a/src/Common/Tests/Formatter/StringFormatterTest.php b/src/Common/Tests/Formatter/StringFormatterTest.php
index 1d0dae347..4dc013982 100644
--- a/src/Common/Tests/Formatter/StringFormatterTest.php
+++ b/src/Common/Tests/Formatter/StringFormatterTest.php
@@ -12,11 +12,12 @@
 
 use Geocoder\Formatter\StringFormatter;
 use Geocoder\Model\LocationFactory;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author William Durand <william.durand1@gmail.com>
  */
-class StringFormatterTest extends \PHPUnit_Framework_TestCase
+class StringFormatterTest extends TestCase
 {
     /**
      * @var StringFormatter
diff --git a/src/Common/Tests/Model/AddressCollectionTest.php b/src/Common/Tests/Model/AddressCollectionTest.php
index b9e624ef5..88e3203e2 100644
--- a/src/Common/Tests/Model/AddressCollectionTest.php
+++ b/src/Common/Tests/Model/AddressCollectionTest.php
@@ -11,11 +11,12 @@
 namespace Geocoder\Tests\Model;
 
 use Geocoder\Model\AddressCollection;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author Tobias Nyholm <tobias.nyholm@gmail.com>
  */
-class AddressCollectionTest extends \PHPUnit_Framework_TestCase
+class AddressCollectionTest extends TestCase
 {
     /**
      * @expectedException \Geocoder\Exception\CollectionIsEmpty
diff --git a/src/Common/Tests/Model/AddressTest.php b/src/Common/Tests/Model/AddressTest.php
index 9863e3466..aff9ae39f 100644
--- a/src/Common/Tests/Model/AddressTest.php
+++ b/src/Common/Tests/Model/AddressTest.php
@@ -12,11 +12,12 @@
 
 use Geocoder\Model\Address;
 use Geocoder\Model\LocationFactory;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author Antoine Lemaire <lemaireantoine@hotmail.com>
  */
-class AddressTest extends \PHPUnit_Framework_TestCase
+class AddressTest extends TestCase
 {
     public function testDumpEmptyAddress()
     {
diff --git a/src/Common/Tests/Model/LocationFactoryTest.php b/src/Common/Tests/Model/LocationFactoryTest.php
index addc34732..a2677ae2c 100644
--- a/src/Common/Tests/Model/LocationFactoryTest.php
+++ b/src/Common/Tests/Model/LocationFactoryTest.php
@@ -13,12 +13,13 @@
 use Geocoder\Model\AddressCollection;
 use Geocoder\Model\LocationFactory;
 use Geocoder\Location;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author Antoine Corcy <contact@sbin.dk>
  * @author William Durand <william.durand1@gmail.com>
  */
-class LocationFactoryTest extends \PHPUnit_Framework_TestCase
+class LocationFactoryTest extends TestCase
 {
     public function testCreateFromArray()
     {
diff --git a/src/Common/Tests/ProviderAggregatorTest.php b/src/Common/Tests/ProviderAggregatorTest.php
index 3977211ac..680382218 100644
--- a/src/Common/Tests/ProviderAggregatorTest.php
+++ b/src/Common/Tests/ProviderAggregatorTest.php
@@ -16,11 +16,12 @@
 use Geocoder\ProviderAggregator;
 use Geocoder\Provider\LocaleAwareGeocoder;
 use Geocoder\Provider\Provider;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author William Durand <william.durand1@gmail.com>
  */
-class ProviderAggregatorTest extends \PHPUnit_Framework_TestCase
+class ProviderAggregatorTest extends TestCase
 {
     /**
      * @var TestableGeocoder
diff --git a/src/Common/Tests/TimedGeocoderTest.php b/src/Common/Tests/TimedGeocoderTest.php
index b77d91d1b..c275d6a74 100644
--- a/src/Common/Tests/TimedGeocoderTest.php
+++ b/src/Common/Tests/TimedGeocoderTest.php
@@ -12,9 +12,10 @@
 
 use Geocoder\Provider\Provider;
 use Geocoder\TimedGeocoder;
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Stopwatch\Stopwatch;
 
-class TimedGeocoderTest extends \PHPUnit_Framework_TestCase
+class TimedGeocoderTest extends TestCase
 {
     /**
      * @var Stopwatch
diff --git a/src/Common/composer.json b/src/Common/composer.json
index 06844f9b0..d051da37a 100644
--- a/src/Common/composer.json
+++ b/src/Common/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "igorw/get-in": "^1.0",
         "psr/http-message-implementation": "^1.0",
         "php-http/client-implementation": "^1.0",
@@ -21,12 +21,12 @@
         "php-http/discovery": "^1.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8",
+        "phpunit/phpunit": "^6.1",
         "symfony/stopwatch": "~2.5",
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "php-http/mock-client": "^0.3.0",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "suggest": {
         "symfony/stopwatch": "If you want to use the TimedGeocoder"
diff --git a/src/Provider/ArcGISOnline/composer.json b/src/Provider/ArcGISOnline/composer.json
index 3fdae3315..6e5ace2bd 100644
--- a/src/Provider/ArcGISOnline/composer.json
+++ b/src/Provider/ArcGISOnline/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\ArcGISOnine\\": "" },
diff --git a/src/Provider/BingMaps/composer.json b/src/Provider/BingMaps/composer.json
index 2815b1c99..e1b69554d 100644
--- a/src/Provider/BingMaps/composer.json
+++ b/src/Provider/BingMaps/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\BingMaps\\": "" },
diff --git a/src/Provider/Chain/composer.json b/src/Provider/Chain/composer.json
index 1d68399da..b5b0c63a6 100644
--- a/src/Provider/Chain/composer.json
+++ b/src/Provider/Chain/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\Chain\\": "" },
diff --git a/src/Provider/FreeGeoIp/composer.json b/src/Provider/FreeGeoIp/composer.json
index 5269c978e..3cdcca54b 100644
--- a/src/Provider/FreeGeoIp/composer.json
+++ b/src/Provider/FreeGeoIp/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\FreeGeoIp\\": "" },
diff --git a/src/Provider/GeoIP2/composer.json b/src/Provider/GeoIP2/composer.json
index a4d7e9ed5..8716843cc 100644
--- a/src/Provider/GeoIP2/composer.json
+++ b/src/Provider/GeoIP2/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\GeoIP2\\": "" },
diff --git a/src/Provider/GeoIPs/composer.json b/src/Provider/GeoIPs/composer.json
index 02c19e2ee..a42d1b075 100644
--- a/src/Provider/GeoIPs/composer.json
+++ b/src/Provider/GeoIPs/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\GeoIPs\\": "" },
diff --git a/src/Provider/GeoPlugin/composer.json b/src/Provider/GeoPlugin/composer.json
index 1f9241d46..d976e696f 100644
--- a/src/Provider/GeoPlugin/composer.json
+++ b/src/Provider/GeoPlugin/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0",
         "igorw/get-in": "^1.0"
     },
@@ -21,7 +21,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\GeoPlugin\\": "" },
diff --git a/src/Provider/Geoip/composer.json b/src/Provider/Geoip/composer.json
index 4adc60c55..d4ba59c99 100644
--- a/src/Provider/Geoip/composer.json
+++ b/src/Provider/Geoip/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\Geoip\\": "" },
diff --git a/src/Provider/Geonames/composer.json b/src/Provider/Geonames/composer.json
index fc376c8e0..b7ec5a94d 100644
--- a/src/Provider/Geonames/composer.json
+++ b/src/Provider/Geonames/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\Geonames\\": "" },
diff --git a/src/Provider/GoogleMaps/composer.json b/src/Provider/GoogleMaps/composer.json
index ac7293156..216c0b59b 100644
--- a/src/Provider/GoogleMaps/composer.json
+++ b/src/Provider/GoogleMaps/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -21,7 +21,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\GoogleMaps\\": "" },
diff --git a/src/Provider/HostIp/composer.json b/src/Provider/HostIp/composer.json
index 1eb15f9f2..7d4a2a0d8 100644
--- a/src/Provider/HostIp/composer.json
+++ b/src/Provider/HostIp/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\HostIp\\": "" },
diff --git a/src/Provider/IpInfoDb/composer.json b/src/Provider/IpInfoDb/composer.json
index ba66adbda..256d6f547 100644
--- a/src/Provider/IpInfoDb/composer.json
+++ b/src/Provider/IpInfoDb/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\IpInfoDb\\": "" },
diff --git a/src/Provider/MapQuest/composer.json b/src/Provider/MapQuest/composer.json
index 73cf7bac0..fb5a111e5 100644
--- a/src/Provider/MapQuest/composer.json
+++ b/src/Provider/MapQuest/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\MapQuest\\": "" },
diff --git a/src/Provider/Mapzen/composer.json b/src/Provider/Mapzen/composer.json
index a8e32b59f..c442c4cc1 100644
--- a/src/Provider/Mapzen/composer.json
+++ b/src/Provider/Mapzen/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\Mapzen\\": "" },
diff --git a/src/Provider/MaxMind/composer.json b/src/Provider/MaxMind/composer.json
index a500e4bcc..802db166f 100644
--- a/src/Provider/MaxMind/composer.json
+++ b/src/Provider/MaxMind/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0",
         "igorw/get-in": "^1.0"
     },
@@ -21,7 +21,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\MaxMind\\": "" },
diff --git a/src/Provider/MaxMindBinary/Tests/MaxMindBinaryTest.php b/src/Provider/MaxMindBinary/Tests/MaxMindBinaryTest.php
index ed92a93ed..bc8ff10da 100644
--- a/src/Provider/MaxMindBinary/Tests/MaxMindBinaryTest.php
+++ b/src/Provider/MaxMindBinary/Tests/MaxMindBinaryTest.php
@@ -29,11 +29,11 @@ public function setUp()
     public static function setUpBeforeClass()
     {
         if (false == function_exists('geoip_open')) {
-            throw new \PHPUnit_Framework_SkippedTestError('The maxmind\'s official lib required to run these tests.');
+            self::markTestSkipped('The maxmind\'s official lib required to run these tests.');
         }
 
         if (false == function_exists('GeoIP_record_by_addr')) {
-            throw new \PHPUnit_Framework_SkippedTestError('The maxmind\'s official lib required to run these tests.');
+            self::markTestSkipped('The maxmind\'s official lib required to run these tests.');
         }
     }
 
diff --git a/src/Provider/MaxMindBinary/composer.json b/src/Provider/MaxMindBinary/composer.json
index d1598c0db..dce58b40f 100644
--- a/src/Provider/MaxMindBinary/composer.json
+++ b/src/Provider/MaxMindBinary/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\MaxMindBinary\\": "" },
diff --git a/src/Provider/Nominatim/composer.json b/src/Provider/Nominatim/composer.json
index 96ee51c0d..c25744487 100644
--- a/src/Provider/Nominatim/composer.json
+++ b/src/Provider/Nominatim/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\Nominatim\\": "" },
diff --git a/src/Provider/OpenCage/composer.json b/src/Provider/OpenCage/composer.json
index 6d8305925..1e7c94cc6 100644
--- a/src/Provider/OpenCage/composer.json
+++ b/src/Provider/OpenCage/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\OpenCage\\": "" },
diff --git a/src/Provider/TomTom/composer.json b/src/Provider/TomTom/composer.json
index 6885fb977..8fc2e7d57 100644
--- a/src/Provider/TomTom/composer.json
+++ b/src/Provider/TomTom/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\TomTom\\": "" },
diff --git a/src/Provider/Yandex/composer.json b/src/Provider/Yandex/composer.json
index 31b63a5c8..182a6d9fa 100644
--- a/src/Provider/Yandex/composer.json
+++ b/src/Provider/Yandex/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.0",
         "willdurand/geocoder": "^4.0"
     },
     "require-dev": {
@@ -20,7 +20,7 @@
         "php-http/message": "^1.0",
         "php-http/curl-client": "^1.7",
         "symfony/phpunit-bridge": "^3.2",
-        "guzzlehttp/psr7": "^1.4"
+        "nyholm/psr7": "^0.2.2"
     },
     "autoload": {
         "psr-4": { "Geocoder\\Provider\\Yandex\\": "" },
diff --git a/tests/CachedResponseClient.php b/tests/CachedResponseClient.php
index 1473dff58..92f8c94b8 100644
--- a/tests/CachedResponseClient.php
+++ b/tests/CachedResponseClient.php
@@ -11,9 +11,9 @@
 namespace Geocoder\Tests;
 
 use Http\Client\HttpClient;
+use Nyholm\Psr7\Factory\StreamFactory;
+use Nyholm\Psr7\Response;
 use Psr\Http\Message\RequestInterface;
-use GuzzleHttp\Psr7\Response;
-use GuzzleHttp\Psr7;
 
 class CachedResponseClient implements HttpClient
 {
@@ -46,7 +46,7 @@ public function sendRequest(RequestInterface $request)
 
         $file = sprintf('%s/%s/%s_%s', __DIR__, $this->cacheDir, $host, sha1($url));
         if ($this->useCache && is_file($file) && is_readable($file)) {
-            return new Response(200, [], Psr7\stream_for(unserialize(file_get_contents($file))));
+            return new Response(200, [], (new StreamFactory())->createStream(unserialize(file_get_contents($file))));
         }
 
         $response = $this->delegate->sendRequest($request);
diff --git a/tests/Functional/LiskovSubstitutionPrincipleTest.php b/tests/Functional/LiskovSubstitutionPrincipleTest.php
index 409ad7695..4aed0ab4d 100644
--- a/tests/Functional/LiskovSubstitutionPrincipleTest.php
+++ b/tests/Functional/LiskovSubstitutionPrincipleTest.php
@@ -29,14 +29,23 @@
 use Geocoder\Tests\CachedResponseClient;
 use Http\Client\HttpClient;
 use Http\Client\Curl\Client as HttplugClient;
+use Http\Discovery\ClassDiscovery;
+use PHPUnit\Framework\TestCase;
 
 /**
  * Test all adapters and make sure they provide the similar result.
  *
  * @author Tobias Nyholm <tobias.nyholm@gmail.com>
  */
-class LiskovSubstitutionPrincipleTest extends \PHPUnit_Framework_TestCase
+class LiskovSubstitutionPrincipleTest extends TestCase
 {
+    public function __construct($name = null, array $data = [], $dataName = '')
+    {
+        ClassDiscovery::prependStrategy('\Nyholm\Psr7\Httplug\DiscoveryStrategy');
+
+        parent::__construct($name, $data, $dataName);
+    }
+
     /**
      * @param Provider $provider
      * @dataProvider getWorldWideProvider
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 54902c933..5a998fba9 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -11,10 +11,11 @@
 namespace Geocoder\Tests;
 
 use Geocoder\Model\LocationFactory;
-use GuzzleHttp\Psr7\Response;
 use Http\Client\HttpClient;
+use Http\Discovery\ClassDiscovery;
 use Http\Mock\Client as MockClient;
 use Http\Client\Curl\Client as HttplugClient;
+use Nyholm\Psr7\Response;
 use Psr\Http\Message\RequestInterface;
 use Psr\Http\Message\ResponseInterface;
 
@@ -23,8 +24,14 @@
  *
  * @deprecated Use geocoder-php/provider-integration-tests instead
  */
-abstract class TestCase extends \PHPUnit_Framework_TestCase
+abstract class TestCase extends \PHPUnit\Framework\TestCase
 {
+    public static function setUpBeforeClass()
+    {
+        parent::setUpBeforeClass();
+        ClassDiscovery::prependStrategy('\Nyholm\Psr7\Httplug\DiscoveryStrategy');
+    }
+
     /**
      * @param null|object $expects
      *