diff --git a/package.json b/package.json
index 4590ec3..e012ef7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "bs58",
-  "version": "3.1.0",
+  "version": "4.0.0",
   "description": "Base 58 encoding / decoding",
   "keywords": [
     "base58",
@@ -31,6 +31,6 @@
     "unit": "mocha"
   },
   "dependencies": {
-    "base-x": "^1.1.0"
+    "base-x": "^2.0.1"
   }
 }