diff --git a/src/Notyf/Prime/.github/workflows/tests.yaml b/src/Notyf/Prime/.github/workflows/tests.yaml
index cab1977a..630fbe54 100644
--- a/src/Notyf/Prime/.github/workflows/tests.yaml
+++ b/src/Notyf/Prime/.github/workflows/tests.yaml
@@ -33,6 +33,10 @@ jobs:
                     php-version: ${{ matrix.php }}
                     coverage: none
 
+            -   name: Require phpunit 5.7 for php >= 5.6
+                if: matrix.php >= 5.6
+                run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
+
             -   name: Require phpunit 6 for php >= 7.0
                 if: matrix.php >= 7.0
                 run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
diff --git a/src/Pnotify/Prime/.github/workflows/tests.yaml b/src/Pnotify/Prime/.github/workflows/tests.yaml
index c09f0dbc..093fc338 100644
--- a/src/Pnotify/Prime/.github/workflows/tests.yaml
+++ b/src/Pnotify/Prime/.github/workflows/tests.yaml
@@ -33,6 +33,10 @@ jobs:
                     php-version: ${{ matrix.php }}
                     coverage: none
 
+            -   name: Require phpunit 5.7 for php >= 5.6
+                if: matrix.php >= 5.6
+                run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
+
             -   name: Require phpunit 6 for php >= 7.0
                 if: matrix.php >= 7.0
                 run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
diff --git a/src/Prime/.github/workflows/tests.yaml b/src/Prime/.github/workflows/tests.yaml
index c09f0dbc..093fc338 100644
--- a/src/Prime/.github/workflows/tests.yaml
+++ b/src/Prime/.github/workflows/tests.yaml
@@ -33,6 +33,10 @@ jobs:
                     php-version: ${{ matrix.php }}
                     coverage: none
 
+            -   name: Require phpunit 5.7 for php >= 5.6
+                if: matrix.php >= 5.6
+                run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
+
             -   name: Require phpunit 6 for php >= 7.0
                 if: matrix.php >= 7.0
                 run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
diff --git a/src/SweetAlert/Prime/.github/workflows/tests.yaml b/src/SweetAlert/Prime/.github/workflows/tests.yaml
index c09f0dbc..093fc338 100644
--- a/src/SweetAlert/Prime/.github/workflows/tests.yaml
+++ b/src/SweetAlert/Prime/.github/workflows/tests.yaml
@@ -33,6 +33,10 @@ jobs:
                     php-version: ${{ matrix.php }}
                     coverage: none
 
+            -   name: Require phpunit 5.7 for php >= 5.6
+                if: matrix.php >= 5.6
+                run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
+
             -   name: Require phpunit 6 for php >= 7.0
                 if: matrix.php >= 7.0
                 run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
diff --git a/src/Toastr/Prime/.github/workflows/tests.yaml b/src/Toastr/Prime/.github/workflows/tests.yaml
index c09f0dbc..093fc338 100644
--- a/src/Toastr/Prime/.github/workflows/tests.yaml
+++ b/src/Toastr/Prime/.github/workflows/tests.yaml
@@ -33,6 +33,10 @@ jobs:
                     php-version: ${{ matrix.php }}
                     coverage: none
 
+            -   name: Require phpunit 5.7 for php >= 5.6
+                if: matrix.php >= 5.6
+                run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
+
             -   name: Require phpunit 6 for php >= 7.0
                 if: matrix.php >= 7.0
                 run: COMPOSER_MEMORY_LIMIT=-1 composer require "phpunit/phpunit:6.*" --no-interaction --no-update
diff --git a/src/Toastr/Prime/composer.json b/src/Toastr/Prime/composer.json
index e3dea930..60200589 100644
--- a/src/Toastr/Prime/composer.json
+++ b/src/Toastr/Prime/composer.json
@@ -41,7 +41,10 @@
         }
     },
     "config": {
-        "sort-packages": true
+        "sort-packages": true,
+        "platform": {
+            "php": "5.6"
+        }
     },
     "minimum-stability": "dev",
     "prefer-stable": true