diff --git a/lib/models/directbilling/transaction/db.transaction.d.ts b/lib/models/directbilling/transaction/db.transaction.d.ts
index 887586d..5a4dbf1 100644
--- a/lib/models/directbilling/transaction/db.transaction.d.ts
+++ b/lib/models/directbilling/transaction/db.transaction.d.ts
@@ -1,7 +1,7 @@
 import { DbTransactionStatus } from './db.transaction.status';
 import { DbProvider } from '../service/db.provider';
 export interface DbTransaction {
-    id: number;
+    id: string;
     status: DbTransactionStatus;
     phoneNumber?: string;
     control: string;
diff --git a/lib/models/directbilling/transaction/partial.db.transaction.d.ts b/lib/models/directbilling/transaction/partial.db.transaction.d.ts
index 0ee0b1d..eb3b1bb 100644
--- a/lib/models/directbilling/transaction/partial.db.transaction.d.ts
+++ b/lib/models/directbilling/transaction/partial.db.transaction.d.ts
@@ -1,7 +1,7 @@
 import { DbProvider } from '../service/db.provider';
 import { DbTransactionStatus } from './db.transaction.status';
 export interface PartialDbTransaction {
-    id: number;
+    id: string;
     status: DbTransactionStatus;
     value: number;
     value_netto: number;
diff --git a/lib/payments/directbilling.d.ts b/lib/payments/directbilling.d.ts
index 248c542..7f73ff8 100644
--- a/lib/payments/directbilling.d.ts
+++ b/lib/payments/directbilling.d.ts
@@ -17,7 +17,7 @@ export declare class DirectBilling {
     calculateCommission(serviceId: number, amount: number): Promise<DbCalculation | undefined>;
     getTransactions(serviceId: number): Promise<PartialDbTransaction[]>;
     getTransactionsPaginated(serviceId: number, page?: number, pageSize?: number): Promise<PaginatedResponse<PartialDbTransaction>>;
-    getTransaction(serviceId: number, transactionId: number): Promise<DbTransaction | undefined>;
+    getTransaction(serviceId: number, transactionId: string): Promise<DbTransaction | undefined>;
     createTransaction(serviceId: number, key: string, request: DbTransactionRequest): Promise<DbGenerationResponse | undefined>;
     checkNotification(key: string, body: any): DbTransaction | undefined;
     generateSignature(key: string, request: DbTransactionRequest): string;
diff --git a/lib/tests/directbilling.js b/lib/tests/directbilling.js
index ce95c56..24ad90e 100644
--- a/lib/tests/directbilling.js
+++ b/lib/tests/directbilling.js
@@ -24,7 +24,7 @@ const run = () => __awaiter(void 0, void 0, void 0, function* () {
     console.log(yield db.getTransactions(158));
     console.log(yield db.getTransactionsPaginated(158, 1, 100));
     // https://docs-new.simpay.pl/typescript/?typescript#directbilling-pobieranie-informacji-o-transakcji
-    console.log(yield db.getTransaction(158, 559911));
+    console.log(yield db.getTransaction(158, '559911'));
     // https://docs-new.simpay.pl/typescript/?typescript#directbilling-generowanie-transakcji
     console.log(yield db.createTransaction(158, 'key', {
         amount: 10.00,
diff --git a/package.json b/package.json
index 0259e28..a4c7b6e 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "simpay-typescript-api",
   "author": "Rafał Więcek",
-  "version": "2.1.1",
+  "version": "2.1.2",
   "description": "SimPay.pl API",
   "main": "lib/index.js",
   "types": "lib/index.d.ts",
diff --git a/src/models/directbilling/transaction/db.transaction.ts b/src/models/directbilling/transaction/db.transaction.ts
index d786f26..6ac4e0f 100644
--- a/src/models/directbilling/transaction/db.transaction.ts
+++ b/src/models/directbilling/transaction/db.transaction.ts
@@ -2,7 +2,7 @@ import {DbTransactionStatus} from './db.transaction.status';
 import {DbProvider} from '../service/db.provider';
 
 export interface DbTransaction {
-    id: number;
+    id: string;
     status: DbTransactionStatus;
 
     phoneNumber?: string;
diff --git a/src/models/directbilling/transaction/partial.db.transaction.ts b/src/models/directbilling/transaction/partial.db.transaction.ts
index c064314..4ba0972 100644
--- a/src/models/directbilling/transaction/partial.db.transaction.ts
+++ b/src/models/directbilling/transaction/partial.db.transaction.ts
@@ -2,7 +2,7 @@ import {DbProvider} from '../service/db.provider';
 import {DbTransactionStatus} from './db.transaction.status';
 
 export interface PartialDbTransaction {
-    id: number;
+    id: string;
     status: DbTransactionStatus;
 
     value: number;
diff --git a/src/payments/directbilling.ts b/src/payments/directbilling.ts
index ea667c4..45a407d 100644
--- a/src/payments/directbilling.ts
+++ b/src/payments/directbilling.ts
@@ -138,7 +138,7 @@ export class DirectBilling {
     /*
         https://docs-new.simpay.pl/typescript/?typescript#directbilling-pobieranie-informacji-o-transakcji
      */
-    async getTransaction(serviceId: number, transactionId: number): Promise<DbTransaction | undefined> {
+    async getTransaction(serviceId: number, transactionId: string): Promise<DbTransaction | undefined> {
         const transaction = (await this.client.get(`/${serviceId}/transactions/${transactionId}`)).data.data;
 
         transaction.created_at = new Date(transaction.created_at.replace(' ', 'T'));
diff --git a/src/tests/directbilling.ts b/src/tests/directbilling.ts
index 57c2584..cac62a7 100644
--- a/src/tests/directbilling.ts
+++ b/src/tests/directbilling.ts
@@ -19,7 +19,7 @@ const run = async () => {
     console.log( await db.getTransactionsPaginated(158, 1, 100) );
 
     // https://docs-new.simpay.pl/typescript/?typescript#directbilling-pobieranie-informacji-o-transakcji
-    console.log( await db.getTransaction(158, 559911) );
+    console.log( await db.getTransaction(158, '559911') );
 
     // https://docs-new.simpay.pl/typescript/?typescript#directbilling-generowanie-transakcji
     console.log( await db.createTransaction(158, 'key', {