diff --git a/composer.json b/composer.json
index f8b40f8..b145680 100644
--- a/composer.json
+++ b/composer.json
@@ -13,11 +13,11 @@
         }
     ],
     "require": {
-        "php": ">=5.3.0",
+        "php": ">=7.1",
         "ext-mbstring": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8.35"
+        "phpunit/phpunit": "^7.5|^8.5|^9.6"
     },
     "autoload": {
         "psr-0": {"Parsedown": ""}