diff --git a/dub.json b/dub.json
index 88ca118..1929341 100644
--- a/dub.json
+++ b/dub.json
@@ -7,7 +7,7 @@
     ],
     "description": "numpy-like API wrappers of mir",
     "dependencies": {
-        "mir-random": "~>2.0.0"
+        "mir-random": ">=2.0.0 <3.4.0"
     },
     "copyright": "Copyright © 2017, karita",
     "license": "BSL-1.0",
diff --git a/source/numir/random.d b/source/numir/random.d
index 65670d0..f6723c8 100644
--- a/source/numir/random.d
+++ b/source/numir/random.d
@@ -22,7 +22,7 @@ class RNG
         {
             synchronized(RNG.classinfo)
             {
-                _rng = new Random(unpredictableSeed);
+                _rng = new Random(unpredictableSeed!size_t);
             }
         }
         return *_rng;