diff --git a/phonejs/dx.phonejs.d.ts b/phonejs/dx.phonejs.d.ts
index 5755fcfc89..a3813eb565 100644
--- a/phonejs/dx.phonejs.d.ts
+++ b/phonejs/dx.phonejs.d.ts
@@ -422,13 +422,13 @@ declare module DevExpress.framework {
     export interface IStorage {
         getItem(key: string): any;
         setItem(key: string, value: any): void;
-        removeItem(key: string);
+        removeItem(key: string): void;
     }
     export class MemoryKeyValueStorage implements IStorage {
         constructor();
         getItem(key: string): any;
         setItem(key: string, value: any): void;
-        removeItem(key: string);
+        removeItem(key: string): void;
     }
     export interface StateManagerOptions {
         storage?: IStorage;