diff --git a/.travis.yml b/.travis.yml
index b840397..7f8d2e4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -29,20 +29,24 @@ matrix:
   include:
     # Core php tests
     - php: 7.1
-      env: DB=MYSQL PHPUNIT_TEST=core PDO=1
+      env: DB=MYSQL PHPUNIT_TEST=core PDO=1 COMPOSER_ARG=--prefer-lowest
     - php: 7.2
       env: DB=MYSQL PHPUNIT_TEST=framework
     - php: 7.3
       env: DB=PGSQL PHPUNIT_TEST=core
     - php: 7.4
       env: DB=MYSQL PHPUNIT_TEST=core
+    - php: nightly
+      env: DB=MYSQL PHPUNIT_TEST=core COMPOSER_ARG=--ignore-platform-reqs
     # admin php tests
     - php: 7.1
-      env: DB=MYSQL PHPUNIT_TEST=admin PDO=1
+      env: DB=MYSQL PHPUNIT_TEST=admin PDO=1 COMPOSER_ARG=--prefer-lowest
     - php: 7.2
       env: DB=PGSQL PHPUNIT_TEST=admin
     - php: 7.4
       env: DB=MYSQL PHPUNIT_TEST=admin
+    - php: nightly
+      env: DB=MYSQL PHPUNIT_TEST=admin COMPOSER_ARG=--ignore-platform-reqs
     # behat tests
     - php: 7.1
       env: DB=MYSQL BEHAT_TEST="@framework"
diff --git a/composer.json b/composer.json
index d87ce05..951b794 100644
--- a/composer.json
+++ b/composer.json
@@ -3,14 +3,14 @@
     "type": "silverstripe-recipe",
     "description": "The SilverStripe Framework Installer",
     "require": {
-        "php": ">=7.1.0",
+        "php": "^7.1 || ^8",
         "silverstripe/recipe-plugin": "^1.2",
         "silverstripe/recipe-cms": "4.x-dev",
         "silverstripe-themes/simple": "~3.2.0",
         "silverstripe/login-forms": "4.x-dev"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.7",
+        "sminnee/phpunit": "^5.7",
         "sminnee/phpunit-mock-objects": "^3.4.5"
     },
     "extra": {