diff --git a/composer.json b/composer.json
index 886d6eb..2912b97 100644
--- a/composer.json
+++ b/composer.json
@@ -1,5 +1,10 @@
 {
     "require": {
-        "jasig/phpcas" : "*"
+        "jasig/phpcas": "1.3.3"
+    },
+    "config": {
+        "platform": {
+            "php": "7.4.00"
+        }
     }
-}
\ No newline at end of file
+}