diff --git a/dexie/dexie.d.ts b/dexie/dexie.d.ts
index 36bec7b32..d6c26283c 100644
--- a/dexie/dexie.d.ts
+++ b/dexie/dexie.d.ts
@@ -38,7 +38,7 @@ declare class Dexie {
 
     static deepClone(obj: Object): Object;
 
-    version(versionNumber: Number): Dexie.Version
+    version(versionNumber: number): Dexie.Version
 
     on: {
         (eventName: string, subscriber: () => any): void;