diff --git a/composer.json b/composer.json
index a519b953f..268a81e7b 100644
--- a/composer.json
+++ b/composer.json
@@ -28,8 +28,8 @@
         "ext-dom": "*",
         "ext-mbstring": "*",
         "masterminds/html5": "^2.0",
-        "phenx/php-font-lib": ">=0.5.4",
-        "phenx/php-svg-lib": ">=0.3.3"
+        "phenx/php-font-lib": ">=0.5.4 <1.0.0",
+        "phenx/php-svg-lib": ">=0.3.3 <1.0.0"
     },
     "require-dev": {
         "ext-json": "*",