Drop support for io.js, fix minor issue with node extension
diff --git a/templates/package.json.template b/templates/package.json.template
index 316c28e..272a175 100644
--- a/templates/package.json.template
+++ b/templates/package.json.template
@@ -54,7 +54,7 @@
       "poisson-process": "^0.2.1"
     },
     "engines": {
-      "node": ">=1.1.0"
+      "node": ">=4"
     },
     "binary": {
       "module_name": "grpc_node",