diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 1ee352982..b76a06527 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -33,6 +33,10 @@ jobs:
                         tools: "composer:v2"
                         coverage: "none"
                         git-fetch-depth: 1
+                    -   php: 8.0
+                        tools: "composer:v2"
+                        coverage: "pcov"
+                        git-fetch-depth: 1
 
         steps:
             -   uses: actions/checkout@v2
diff --git a/.github/workflows/e2e.yml b/.github/workflows/e2e.yml
new file mode 100644
index 000000000..a4a2eab74
--- /dev/null
+++ b/.github/workflows/e2e.yml
@@ -0,0 +1,60 @@
+name: e2e
+
+on:
+    push:
+        branches: [ master ]
+    pull_request:
+
+jobs:
+
+    e2e:
+        runs-on: ubuntu-latest
+        name: ${{ matrix.e2e }} - ${{ matrix.php }}
+        strategy:
+            fail-fast: false
+            matrix:
+                e2e:
+                    - 'e2e_php_settings_checker'
+                    - 'e2e_scoper_alias'
+                    - 'e2e_scoper_whitelist'
+                    - 'e2e_check_requirements'
+                    - 'e2e_symfony'
+                    - 'e2e_composer_installed_versions'
+                php: [ '7.3', '8.0' ]
+                tools: [ 'composer:v2' ]
+
+        steps:
+            -   uses: actions/checkout@v2
+                with:
+                    fetch-depth: 0
+
+            -   name: Setup PHP
+                uses: shivammathur/setup-php@v2
+                with:
+                    php-version: ${{ matrix.php }}
+                    ini-values: "phar.readonly=0"
+                    tools: ${{ matrix.tools }}
+                    coverage: pcov
+
+            -   name: Get composer cache directory
+                id: composercache
+                run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+            -   name: Cache composer dependencies
+                uses: actions/cache@v2
+                with:
+                    path: ${{ steps.composercache.outputs.dir }}
+                    key: composer-${{ runner.os }}-${{ matrix.php }}-${{ hashFiles('composer.*') }}
+                    restore-keys: |
+                        composer-${{ runner.os }}-${{ matrix.php }}-
+                        composer-${{ runner.os }}-
+                        composer-
+
+            -   name: Install dependencies
+                run: composer install --no-interaction --no-progress --no-suggest --prefer-dist
+
+            -   name: Install requirement-checker dependencies
+                run: composer install --no-interaction --no-progress --prefer-dist --working-dir requirement-checker
+
+            -   name: Run e2e ${{ matrix.e2e }}
+                run: make ${{ matrix.e2e }}
diff --git a/composer.json b/composer.json
index aa22eda7f..bfaea2462 100644
--- a/composer.json
+++ b/composer.json
@@ -41,7 +41,7 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "require": {
-        "php": "^7.3",
+        "php": "^7.3 || ^8.0",
         "ext-phar": "*",
         "amphp/parallel-functions": "^0.1.3",
         "beberlei/assert": "^3.2",
diff --git a/composer.lock b/composer.lock
index 723bd0f25..06f41f4c6 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,20 +4,20 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "8050674eeab1d858123fa1de61f99fae",
+    "content-hash": "10f22f46e2f224ac357bd3f048f17c98",
     "packages": [
         {
             "name": "amphp/amp",
-            "version": "v2.5.0",
+            "version": "v2.5.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/amphp/amp.git",
-                "reference": "f220a51458bf4dd0dedebb171ac3457813c72bbc"
+                "reference": "ecdc3c476b3ccff02f8e5d5bcc04f7ccfd18751c"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/amphp/amp/zipball/f220a51458bf4dd0dedebb171ac3457813c72bbc",
-                "reference": "f220a51458bf4dd0dedebb171ac3457813c72bbc",
+                "url": "https://api.github.com/repos/amphp/amp/zipball/ecdc3c476b3ccff02f8e5d5bcc04f7ccfd18751c",
+                "reference": "ecdc3c476b3ccff02f8e5d5bcc04f7ccfd18751c",
                 "shasum": ""
             },
             "require": {
@@ -85,7 +85,7 @@
             "support": {
                 "irc": "irc://irc.freenode.org/amphp",
                 "issues": "https://github.com/amphp/amp/issues",
-                "source": "https://github.com/amphp/amp/tree/master"
+                "source": "https://github.com/amphp/amp/tree/v2.5.1"
             },
             "funding": [
                 {
@@ -93,7 +93,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2020-07-14T21:47:18+00:00"
+            "time": "2020-11-03T16:23:45+00:00"
         },
         {
             "name": "amphp/byte-stream",
@@ -1820,7 +1820,7 @@
             "support": {
                 "source": "https://github.com/JetBrains/phpstorm-stubs/tree/master"
             },
-            "time": "2020-11-17T11:49:11+00:00"
+            "time": "2020-12-05T10:13:52+00:00"
         },
         {
             "name": "justinrainbow/json-schema",
@@ -2005,29 +2005,29 @@
         },
         {
             "name": "opis/closure",
-            "version": "3.5.7",
+            "version": "3.6.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/opis/closure.git",
-                "reference": "4531e53afe2fc660403e76fb7644e95998bff7bf"
+                "reference": "943b5d70cc5ae7483f6aff6ff43d7e34592ca0f5"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/opis/closure/zipball/4531e53afe2fc660403e76fb7644e95998bff7bf",
-                "reference": "4531e53afe2fc660403e76fb7644e95998bff7bf",
+                "url": "https://api.github.com/repos/opis/closure/zipball/943b5d70cc5ae7483f6aff6ff43d7e34592ca0f5",
+                "reference": "943b5d70cc5ae7483f6aff6ff43d7e34592ca0f5",
                 "shasum": ""
             },
             "require": {
-                "php": "^5.4 || ^7.0"
+                "php": "^5.4 || ^7.0 || ^8.0"
             },
             "require-dev": {
                 "jeremeamia/superclosure": "^2.0",
-                "phpunit/phpunit": "^4.0 || ^5.0 || ^6.0 || ^7.0"
+                "phpunit/phpunit": "^4.0 || ^5.0 || ^6.0 || ^7.0 || ^8.0 || ^9.0"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.5.x-dev"
+                    "dev-master": "3.6.x-dev"
                 }
             },
             "autoload": {
@@ -2064,9 +2064,9 @@
             ],
             "support": {
                 "issues": "https://github.com/opis/closure/issues",
-                "source": "https://github.com/opis/closure/tree/3.5.7"
+                "source": "https://github.com/opis/closure/tree/3.6.1"
             },
-            "time": "2020-09-06T17:02:15+00:00"
+            "time": "2020-11-07T02:01:34+00:00"
         },
         {
             "name": "paragonie/constant_time_encoding",
@@ -5631,7 +5631,7 @@
     "prefer-stable": true,
     "prefer-lowest": false,
     "platform": {
-        "php": "^7.3",
+        "php": "^7.3 || ^8.0",
         "ext-phar": "*",
         "composer-plugin-api": "^1.0 || ^2.0"
     },
diff --git a/fixtures/build/dir011/composer.json b/fixtures/build/dir011/composer.json
index 0bc7b5f93..b0367efb8 100644
--- a/fixtures/build/dir011/composer.json
+++ b/fixtures/build/dir011/composer.json
@@ -7,5 +7,5 @@
             "src/functions.php"
         ]
     },
-    "bin": "index.php"
+    "bin": ["index.php"]
 }
diff --git a/fixtures/build/dir012/composer.json b/fixtures/build/dir012/composer.json
index a9e872cfd..92e1d63d8 100644
--- a/fixtures/build/dir012/composer.json
+++ b/fixtures/build/dir012/composer.json
@@ -20,7 +20,7 @@
             "php": "7.2.9"
         }
     },
-    "bin": "bin/console",
+    "bin": ["bin/console"],
     "autoload": {
         "psr-4": {
             "App\\": "src/"