diff --git a/.styleci.yml b/.styleci.yml
index 5142082..0285f17 100644
--- a/.styleci.yml
+++ b/.styleci.yml
@@ -1,4 +1 @@
 preset: laravel
-
-disabled:
-  - self_accessor
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
index 5fcf3cc..b73cc2a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,22 +9,6 @@ cache:
 matrix:
   fast_finish: true
   include:
-    - php: 7.1
-      env: LARAVEL='5.5.*' PHPUNIT='6.*' COMPOSER_FLAGS='--prefer-lowest'
-    - php: 7.1
-      env: LARAVEL='5.5.*' PHPUNIT='6.*' COMPOSER_FLAGS='--prefer-stable'
-    - php: 7.2
-      env: LARAVEL='5.7.*' PHPUNIT='7.5.*' COMPOSER_FLAGS='--prefer-lowest'
-    - php: 7.2
-      env: LARAVEL='5.7.*' PHPUNIT='7.5.*' COMPOSER_FLAGS='--prefer-stable'
-    - php: 7.3
-      env: LARAVEL='5.7.*' PHPUNIT='7.5.*' COMPOSER_FLAGS='--prefer-lowest'
-    - php: 7.3
-      env: LARAVEL='5.7.*' PHPUNIT='7.5.*' COMPOSER_FLAGS='--prefer-stable'
-    - php: 7.2
-      env: LARAVEL='6.*' PHPUNIT='^8.3' COMPOSER_FLAGS='--prefer-lowest'
-    - php: 7.2
-      env: LARAVEL='6.*' PHPUNIT='^8.3' COMPOSER_FLAGS='--prefer-stable'
     - php: 7.3
       env: LARAVEL='6.*' PHPUNIT='^8.3' COMPOSER_FLAGS='--prefer-lowest'
     - php: 7.3
@@ -37,6 +21,14 @@ matrix:
       env: LARAVEL='7.*' PHPUNIT='^8.3' COMPOSER_FLAGS='--prefer-lowest'
     - php: 7.4
       env: LARAVEL='7.*' PHPUNIT='^8.3' COMPOSER_FLAGS='--prefer-stable'
+    - php: 7.3
+      env: LARAVEL='8.*' PHPUNIT='^9.0' COMPOSER_FLAGS='--prefer-lowest'
+    - php: 7.3
+      env: LARAVEL='8.*' PHPUNIT='^9.0' COMPOSER_FLAGS='--prefer-stable'
+    - php: 7.4
+      env: LARAVEL='8.*' PHPUNIT='^9.0' COMPOSER_FLAGS='--prefer-lowest'
+    - php: 7.4
+      env: LARAVEL='8.*' PHPUNIT='^9.0' COMPOSER_FLAGS='--prefer-stable'
 
 before_install:
   - travis_retry composer self-update
@@ -46,4 +38,4 @@ install:
   - travis_retry composer update ${COMPOSER_FLAGS} --prefer-dist --no-interaction --no-suggest
 
 script:
-  - vendor/bin/phpunit
\ No newline at end of file
+  - vendor/bin/phpunit
diff --git a/composer.json b/composer.json
index bbff336..676ac46 100644
--- a/composer.json
+++ b/composer.json
@@ -7,21 +7,21 @@
         }
     },
     "require": {
-        "php": ">=7.1.0",
-        "illuminate/container": "^5.5|^6.0|^7.0",
-        "illuminate/filesystem": "^5.5|^6.0|^7.0",
-        "illuminate/support": "^5.5|^6.0|^7.0",
+        "php": ">=7.3.0",
+        "illuminate/container": "6.*|7.*|8.*",
+        "illuminate/filesystem": "6.*|7.*|8.*",
+        "illuminate/support": "6.*|7.*|8.*",
         "superbalist/laravel-google-cloud-storage": "^1.0|^2.2",
-        "guzzlehttp/guzzle": "^6.3"
+        "guzzlehttp/guzzle": "^6.3|^7.0.1"
     },
     "require-dev": {
-        "codedungeon/phpunit-result-printer": "^0.26.0",
-        "laravel/laravel": "5.5.*|^6.0|^7.0",
+        "codedungeon/phpunit-result-printer": "^0.28.0",
+        "laravel/laravel": "6.*|7.*|8.*",
         "intervention/image": "^2.4",
         "doctrine/dbal": "^2.5",
         "mockery/mockery": "^1.3",
         "rutorika/sortable": "^4.2|^6.0|^7.0",
-        "phpunit/phpunit": "^6.0|^7.0|^8.0",
+        "phpunit/phpunit": "8.*|9.*",
         "fzaninotto/faker": "^1.4",
         "league/flysystem": "^1.0.8"
     },
diff --git a/tests/Feature/GeneratePlaceholdersTest.php b/tests/Feature/GeneratePlaceholdersTest.php
index 494a950..42ff955 100644
--- a/tests/Feature/GeneratePlaceholdersTest.php
+++ b/tests/Feature/GeneratePlaceholdersTest.php
@@ -25,7 +25,7 @@ public function it_generates_placeholders_and_sets_dimensions()
 
         // It generates placeholder
         $this->assertNotNull($placeholder = $image->refresh()->tiny_placeholder);
-        $this->assertContains('base64', $placeholder);
+        $this->assertStringContainsString('base64', $placeholder);
 
         // It sets dimensions when NULL (for upgrading versions)
         $this->assertNotNull($image->width);
diff --git a/tests/Feature/ImageTest.php b/tests/Feature/ImageTest.php
index 303dae7..f5288ee 100644
--- a/tests/Feature/ImageTest.php
+++ b/tests/Feature/ImageTest.php
@@ -69,9 +69,9 @@ public function it_casts_to_a_responsive_html_img_tag()
     {
         $image = Image::upload(new File(__DIR__.'/../image.jpg'), 'test.jpg');
 
-        $this->assertContains('<img', $html = (string) $image);
-        $this->assertContains('srcset', $html = (string) $image);
-        $this->assertNotContains('sizes', $html = (string) $image);
+        $this->assertStringContainsString('<img', $html = (string) $image);
+        $this->assertStringContainsString('srcset', $html = (string) $image);
+        $this->assertStringNotContainsString('sizes', $html = (string) $image);
     }
 
     /** @test **/
@@ -81,9 +81,9 @@ public function it_casts_to_a_responsive_html_img_tag_with_placeholder_when_enab
 
         $image = Image::upload(new File(__DIR__.'/../image.jpg'), 'test.jpg');
 
-        $this->assertContains('<img', $html = (string) $image);
-        $this->assertContains('srcset', $html = (string) $image);
-        $this->assertContains('sizes', $html = (string) $image);
-        $this->assertContains('onload', $html = (string) $image);
+        $this->assertStringContainsString('<img', $html = (string) $image);
+        $this->assertStringContainsString('srcset', $html = (string) $image);
+        $this->assertStringContainsString('sizes', $html = (string) $image);
+        $this->assertStringContainsString('onload', $html = (string) $image);
     }
 }
diff --git a/tests/Feature/ResponsiveTest.php b/tests/Feature/ResponsiveTest.php
index 480b966..45c80bc 100644
--- a/tests/Feature/ResponsiveTest.php
+++ b/tests/Feature/ResponsiveTest.php
@@ -146,7 +146,7 @@ public function regression__it_handles_none_existent_images()
         $this->assertEquals([], $responsive->get()->all());
         $this->assertNull($responsive->getSrc());
         $this->assertEquals('', $responsive->getSrcset());
-        $this->assertContains('src=""', $responsive->getHtml());
+        $this->assertStringContainsString('src=""', $responsive->getHtml());
         $this->assertEquals([
             'src' => null,
             'srcset' => '',