diff --git a/CHANGELOG.md b/CHANGELOG.md
index ba72fd2..f13e13c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,22 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.0.0] - 2026-08-24
+
+### Added
+
+- Add draft support methods for retentions: `retentions.updateDraft(String id, Map<String, Object> data)`, `retentions.copyToDraft(String id)`, `retentions.stampDraft(String id)`, and `retentions.cancel(String id)`.
+
+- Add `invoices.createZipRequest(Map<String, Object> data)` for `POST /invoices/zip-requests`.
+- Add `invoices.listZipRequests(Map<String, ?> params)` for `GET /invoices/zip-requests`.
+- Add `invoices.retrieveZipRequest(String id)` for `GET /invoices/zip-requests/{id}`.
+- Add `invoices.downloadZipRequestStream(String id)` for streaming `GET /invoices/zip-requests/{id}/zip`.
+
+### Changed
+
+- Change `FacturapiException.getErrorCode()` to return strings, including converted legacy numeric codes.
+- Change `InvoiceItem.property_tax_account` to a list of property tax account numbers.
+
 ## [1.3.0] - 2026-06-07
 
 ### Added
diff --git a/README.es.md b/README.es.md
index 0e1dc20..d5ba3bd 100644
--- a/README.es.md
+++ b/README.es.md
@@ -29,14 +29,14 @@ Maven:
 <dependency>
   <groupId>io.facturapi</groupId>
   <artifactId>facturapi-java</artifactId>
-  <version>1.1.0</version>
+  <version>2.0.0</version>
 </dependency>
 ```
 
 Gradle:
 
 ```gradle
-implementation("io.facturapi:facturapi-java:1.1.0")
+implementation("io.facturapi:facturapi-java:2.0.0")
 ```
 
 ## Inicio rápido
diff --git a/README.md b/README.md
index fe0f67b..b2ca541 100644
--- a/README.md
+++ b/README.md
@@ -29,14 +29,14 @@ Maven:
 <dependency>
   <groupId>io.facturapi</groupId>
   <artifactId>facturapi-java</artifactId>
-  <version>1.1.0</version>
+  <version>2.0.0</version>
 </dependency>
 ```
 
 Gradle:
 
 ```gradle
-implementation("io.facturapi:facturapi-java:1.1.0")
+implementation("io.facturapi:facturapi-java:2.0.0")
 ```
 
 ## Quickstart
diff --git a/pom.xml b/pom.xml
index 4235f4a..a69187f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
 
   <groupId>io.facturapi</groupId>
   <artifactId>facturapi-java</artifactId>
-  <version>1.3.0</version>
+  <version>2.0.0</version>
   <name>facturapi-java</name>
   <description>Official Java SDK for Facturapi</description>
   <url>https://github.com/facturapi/facturapi-java</url>
diff --git a/src/main/java/io/facturapi/FacturapiException.java b/src/main/java/io/facturapi/FacturapiException.java
index 0e0839c..482baed 100644
--- a/src/main/java/io/facturapi/FacturapiException.java
+++ b/src/main/java/io/facturapi/FacturapiException.java
@@ -7,7 +7,7 @@
 
 public class FacturapiException extends RuntimeException {
   private final int statusCode;
-  private final Object errorCode;
+  private final String errorCode;
   private final String errorPath;
   private final String errorLocation;
   private final JsonNode errors;
@@ -29,14 +29,14 @@ public FacturapiException(String message, Throwable cause) {
     this.headers = Collections.emptyMap();
   }
 
-  public FacturapiException(String message, int statusCode, Object errorCode, String errorPath) {
+  public FacturapiException(String message, int statusCode, String errorCode, String errorPath) {
     this(message, statusCode, errorCode, errorPath, null, null, null, Collections.emptyMap());
   }
 
   public FacturapiException(
     String message,
     int statusCode,
-    Object errorCode,
+    String errorCode,
     String errorPath,
     String errorLocation,
     JsonNode errors,
@@ -57,7 +57,7 @@ public int getStatusCode() {
     return statusCode;
   }
 
-  public Object getErrorCode() {
+  public String getErrorCode() {
     return errorCode;
   }
 
diff --git a/src/main/java/io/facturapi/http/FacturapiHttpClient.java b/src/main/java/io/facturapi/http/FacturapiHttpClient.java
index 0fee0d7..a25c3b4 100644
--- a/src/main/java/io/facturapi/http/FacturapiHttpClient.java
+++ b/src/main/java/io/facturapi/http/FacturapiHttpClient.java
@@ -210,7 +210,7 @@ private static JsonNode firstDefined(JsonNode node, String... keys) {
   private FacturapiException buildApiException(String bodyText, Response response) {
     int statusCode = response.code();
     int resolvedStatus = statusCode;
-    Object errorCode = null;
+    String errorCode = null;
     String errorPath = null;
     String errorLocation = null;
     JsonNode errors = null;
@@ -245,18 +245,8 @@ private FacturapiException buildApiException(String bodyText, Response response)
           }
 
           JsonNode codeNode = firstDefined(root, "code");
-          if (codeNode != null && !codeNode.isNull()) {
-            if (codeNode.isTextual()) {
-              errorCode = codeNode.asText();
-            } else if (codeNode.isIntegralNumber()) {
-              errorCode = codeNode.intValue();
-            } else if (codeNode.isNumber()) {
-              errorCode = codeNode.numberValue();
-            } else if (codeNode.isBoolean()) {
-              errorCode = codeNode.asBoolean();
-            } else {
-              errorCode = codeNode.toString();
-            }
+          if (codeNode != null && (codeNode.isTextual() || codeNode.isNumber())) {
+            errorCode = codeNode.asText();
           }
 
           JsonNode pathNode = firstDefined(root, "path");
diff --git a/src/main/java/io/facturapi/models/InvoiceItem.java b/src/main/java/io/facturapi/models/InvoiceItem.java
index adcb675..dd35db8 100644
--- a/src/main/java/io/facturapi/models/InvoiceItem.java
+++ b/src/main/java/io/facturapi/models/InvoiceItem.java
@@ -14,7 +14,8 @@ public class InvoiceItem {
   private InvoiceItemThirdParty thirdParty;
   private String complement;
   private List<InvoiceItemPart> parts = new ArrayList<>();
-  private String propertyTaxAccount;
+  @JsonProperty("property_tax_account")
+  private List<String> propertyTaxAccounts = new ArrayList<>();
 
   public Double getQuantity() { return quantity; }
   public void setQuantity(Double quantity) { this.quantity = quantity; }
@@ -30,6 +31,8 @@ public class InvoiceItem {
   public void setComplement(String complement) { this.complement = complement; }
   public List<InvoiceItemPart> getParts() { return parts; }
   public void setParts(List<InvoiceItemPart> parts) { this.parts = parts; }
-  public String getPropertyTaxAccount() { return propertyTaxAccount; }
-  public void setPropertyTaxAccount(String propertyTaxAccount) { this.propertyTaxAccount = propertyTaxAccount; }
+  @JsonProperty("property_tax_account")
+  public List<String> getPropertyTaxAccounts() { return propertyTaxAccounts; }
+  @JsonProperty("property_tax_account")
+  public void setPropertyTaxAccounts(List<String> propertyTaxAccounts) { this.propertyTaxAccounts = propertyTaxAccounts; }
 }
diff --git a/src/main/java/io/facturapi/resources/InvoicesResource.java b/src/main/java/io/facturapi/resources/InvoicesResource.java
index f0d2911..6dac015 100644
--- a/src/main/java/io/facturapi/resources/InvoicesResource.java
+++ b/src/main/java/io/facturapi/resources/InvoicesResource.java
@@ -142,6 +142,63 @@ public InputStream downloadZipStream(String id) {
     return client.getStream("/invoices/" + id + "/zip");
   }
 
+  /**
+   * Creates a ZIP request or returns the existing request for the same criteria.
+   *
+   * @param data ZIP request criteria.
+   * @return ZIP request data.
+   * @see <a href="https://docs.facturapi.io/api#tag/Invoices">API reference</a>
+   */
+  public Map<String, Object> createZipRequest(Map<String, Object> data) {
+    return post(
+      "/invoices/zip-requests",
+      data,
+      null,
+      new TypeReference<Map<String, Object>>() {}
+    );
+  }
+
+  /**
+   * Gets a paginated list of ZIP requests.
+   *
+   * @param params Search and pagination parameters.
+   * @return Paginated ZIP request result.
+   * @see <a href="https://docs.facturapi.io/api#tag/Invoices">API reference</a>
+   */
+  public SearchResult<Map<String, Object>> listZipRequests(Map<String, ?> params) {
+    return get(
+      "/invoices/zip-requests",
+      params,
+      new TypeReference<SearchResult<Map<String, Object>>>() {}
+    );
+  }
+
+  /**
+   * Gets a ZIP request by id.
+   *
+   * @param id ZIP request id.
+   * @return ZIP request data.
+   * @see <a href="https://docs.facturapi.io/api#tag/Invoices">API reference</a>
+   */
+  public Map<String, Object> retrieveZipRequest(String id) {
+    return get(
+      "/invoices/zip-requests/" + id,
+      null,
+      new TypeReference<Map<String, Object>>() {}
+    );
+  }
+
+  /**
+   * Downloads the ZIP generated for a request.
+   *
+   * @param id ZIP request id.
+   * @return ZIP stream. Caller owns closing it.
+   * @see <a href="https://docs.facturapi.io/api#tag/Invoices">API reference</a>
+   */
+  public InputStream downloadZipRequestStream(String id) {
+    return client.getStream("/invoices/zip-requests/" + id + "/zip");
+  }
+
   /**
    * Downloads the cancellation receipt XML file.
    *
diff --git a/src/main/java/io/facturapi/resources/RetentionsResource.java b/src/main/java/io/facturapi/resources/RetentionsResource.java
index 4fd50fc..5eafbd7 100644
--- a/src/main/java/io/facturapi/resources/RetentionsResource.java
+++ b/src/main/java/io/facturapi/resources/RetentionsResource.java
@@ -19,7 +19,7 @@ public RetentionsResource(FacturapiHttpClient client) {
   }
 
   /**
-   * Creates a new valid retention (CFDI).
+   * Creates a new retention (CFDI).
    *
    * @param data Retention payload.
    * @return Created retention.
@@ -63,6 +63,51 @@ public Retention cancel(String id, Map<String, ?> params) {
     return delete("/retentions/" + id, params, Retention.class);
   }
 
+  /**
+   * Cancels a retention, or deletes it directly when it is a draft.
+   *
+   * @param id Retention id.
+   * @return Canceled or deleted retention.
+   * @see <a href="https://docs.facturapi.io/api#operation/cancelRetention">API reference</a>
+   */
+  public Retention cancel(String id) {
+    return delete("/retentions/" + id, null, Retention.class);
+  }
+
+  /**
+   * Updates a draft retention.
+   *
+   * @param id Retention id.
+   * @param data Retention updates.
+   * @return Updated draft retention.
+   * @see <a href="https://docs.facturapi.io/api#operation/updateDraftRetention">API reference</a>
+   */
+  public Retention updateDraft(String id, Map<String, Object> data) {
+    return put("/retentions/" + id, data, null, Retention.class);
+  }
+
+  /**
+   * Creates a draft copy from an existing retention.
+   *
+   * @param id Retention id.
+   * @return Draft retention.
+   * @see <a href="https://docs.facturapi.io/api#operation/copyToDraftRetention">API reference</a>
+   */
+  public Retention copyToDraft(String id) {
+    return post("/retentions/" + id + "/copy", null, null, Retention.class);
+  }
+
+  /**
+   * Stamps an existing draft retention.
+   *
+   * @param id Retention id.
+   * @return Stamped retention.
+   * @see <a href="https://docs.facturapi.io/api#operation/stampDraftRetention">API reference</a>
+   */
+  public Retention stampDraft(String id) {
+    return post("/retentions/" + id + "/stamp", null, null, Retention.class);
+  }
+
   /**
    * Sends the retention to the customer's email.
    *
diff --git a/src/test/java/io/facturapi/FacturapiHttpClientTest.java b/src/test/java/io/facturapi/FacturapiHttpClientTest.java
index 4917970..e8d6eac 100644
--- a/src/test/java/io/facturapi/FacturapiHttpClientTest.java
+++ b/src/test/java/io/facturapi/FacturapiHttpClientTest.java
@@ -77,4 +77,23 @@ void throwsFacturapiExceptionWithApiMessage() {
     assertEquals("3", ex.getHeaders().get("Retry-After").get(0));
     assertEquals("log_123", ex.getHeaders().get("x-facturapi-log-id").get(0));
   }
+
+  @Test
+  void convertsNumericApiErrorCodesToStrings() {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueJson(400, "{\"message\":\"Invalid customer\",\"code\":400}");
+
+    FacturapiHttpClient client = new FacturapiHttpClient(
+      FacturapiConfig.builder("sk_test_123")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    FacturapiException ex = assertThrows(
+      FacturapiException.class,
+      () -> client.get("/customers/cus_1", null, GenericResponse.class)
+    );
+
+    assertEquals("400", ex.getErrorCode());
+  }
 }
diff --git a/src/test/java/io/facturapi/FacturapiResourcesTest.java b/src/test/java/io/facturapi/FacturapiResourcesTest.java
index b523184..ef43828 100644
--- a/src/test/java/io/facturapi/FacturapiResourcesTest.java
+++ b/src/test/java/io/facturapi/FacturapiResourcesTest.java
@@ -16,10 +16,12 @@
 import io.facturapi.enums.Taxability;
 import io.facturapi.http.FacturapiConfig;
 import io.facturapi.models.Customer;
+import io.facturapi.models.InvoiceItem;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
 import java.time.Instant;
 import java.time.LocalDate;
+import java.util.List;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
@@ -112,6 +114,192 @@ void invoicePdfCanBeStreamed() throws Exception {
     assertEquals("/v2/invoices/inv_1/pdf", request.uri().getPath());
   }
 
+  @Test
+  void retentionDraftCreateSupportsDraftStatus() {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueJson(200, "{\"id\":\"ret_draft_1\",\"status\":\"draft\"}");
+
+    Facturapi sdk = new Facturapi(
+      FacturapiConfig.builder("sk_test")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    Map<String, Object> payload = new java.util.HashMap<>();
+    payload.put("status", "draft");
+    payload.put("customer", null);
+
+    var response = sdk.retentions().create(payload);
+
+    assertEquals("ret_draft_1", response.getId());
+    assertEquals("draft", response.getStatus());
+    var request = httpClient.requests().get(0);
+    assertEquals("POST", request.method());
+    assertEquals("/v2/retentions", request.uri().getPath());
+    assertTrue(request.bodyUtf8().contains("\"status\":\"draft\""));
+    assertTrue(request.bodyUtf8().contains("\"customer\":null"));
+  }
+
+  @Test
+  void retentionDraftUpdateUsesExpectedPath() {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueJson(200, "{\"id\":\"ret_1\",\"folio_int\":\"R-2026-001\"}");
+
+    Facturapi sdk = new Facturapi(
+      FacturapiConfig.builder("sk_test")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    var response = sdk.retentions().updateDraft("ret_1", Map.of("folio_int", "R-2026-001"));
+
+    assertEquals("ret_1", response.getId());
+    assertEquals("R-2026-001", response.getFolioInt());
+    var request = httpClient.requests().get(0);
+    assertEquals("PUT", request.method());
+    assertEquals("/v2/retentions/ret_1", request.uri().getPath());
+    assertTrue(request.bodyUtf8().contains("\"folio_int\":\"R-2026-001\""));
+  }
+
+  @Test
+  void retentionDraftCopyAndStampUseExpectedPaths() {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueJson(200, "{\"id\":\"ret_copy_1\",\"status\":\"draft\"}");
+    httpClient.enqueueJson(200, "{\"id\":\"ret_1\",\"status\":\"valid\"}");
+
+    Facturapi sdk = new Facturapi(
+      FacturapiConfig.builder("sk_test")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    var draft = sdk.retentions().copyToDraft("ret_1");
+    var stamped = sdk.retentions().stampDraft("ret_copy_1");
+
+    assertEquals("ret_copy_1", draft.getId());
+    assertEquals("ret_1", stamped.getId());
+    assertEquals("POST", httpClient.requests().get(0).method());
+    assertEquals("/v2/retentions/ret_1/copy", httpClient.requests().get(0).uri().getPath());
+    assertEquals("POST", httpClient.requests().get(1).method());
+    assertEquals("/v2/retentions/ret_copy_1/stamp", httpClient.requests().get(1).uri().getPath());
+  }
+
+  @Test
+  void retentionDraftCancelAndListUseExpectedPaths() {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueJson(200, "{\"id\":\"ret_draft_1\",\"status\":\"canceled\"}");
+    httpClient.enqueueJson(200, "{\"data\":[{\"id\":\"ret_draft_2\",\"status\":\"draft\"}]}");
+
+    Facturapi sdk = new Facturapi(
+      FacturapiConfig.builder("sk_test")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    var deleted = sdk.retentions().cancel("ret_draft_1");
+    var drafts = sdk.retentions().list(Map.of("status", "draft"));
+
+    assertEquals("ret_draft_1", deleted.getId());
+    assertEquals(1, drafts.getData().size());
+    assertEquals("DELETE", httpClient.requests().get(0).method());
+    assertEquals("/v2/retentions/ret_draft_1", httpClient.requests().get(0).uri().getPath());
+    var listRequest = httpClient.requests().get(1);
+    assertEquals("GET", listRequest.method());
+    assertEquals("/v2/retentions?status=draft", listRequest.uri().getPath() + "?" + listRequest.uri().getQuery());
+  }
+
+  @Test
+  void invoiceZipRequestCanBeCreated() {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueJson(200, "{\"id\":\"zip_1\",\"status\":\"pending\"}");
+
+    Facturapi sdk = new Facturapi(
+      FacturapiConfig.builder("sk_test")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    var response = sdk.invoices().createZipRequest(
+      Map.of(
+        "year", 2025,
+        "month", 3,
+        "issuer_type", "issuing",
+        "invoice_types", java.util.List.of("I", "E")
+      )
+    );
+
+    assertEquals("zip_1", response.get("id"));
+    var request = httpClient.requests().get(0);
+    assertEquals("POST", request.method());
+    assertEquals("/v2/invoices/zip-requests", request.uri().getPath());
+    assertTrue(request.bodyUtf8().contains("\"issuer_type\":\"issuing\""));
+  }
+
+  @Test
+  void invoiceZipRequestsCanBeListed() {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueJson(
+      200,
+      "{\"page\":1,\"total_pages\":1,\"total_results\":1,\"data\":[{\"id\":\"zip_1\"}]}"
+    );
+
+    Facturapi sdk = new Facturapi(
+      FacturapiConfig.builder("sk_test")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    var response = sdk.invoices().listZipRequests(
+      Map.of("year", 2025, "month", 3, "status", "finished", "limit", 20, "page", 1)
+    );
+
+    assertEquals("zip_1", response.getData().get(0).get("id"));
+    var request = httpClient.requests().get(0);
+    assertEquals("GET", request.method());
+    assertEquals("/v2/invoices/zip-requests", request.uri().getPath());
+    assertTrue(request.uri().getQuery().contains("year=2025"));
+    assertTrue(request.uri().getQuery().contains("status=finished"));
+  }
+
+  @Test
+  void invoiceZipRequestCanBeRetrieved() {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueJson(200, "{\"id\":\"zip_1\",\"status\":\"finished\"}");
+
+    Facturapi sdk = new Facturapi(
+      FacturapiConfig.builder("sk_test")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    var response = sdk.invoices().retrieveZipRequest("zip_1");
+
+    assertEquals("finished", response.get("status"));
+    var request = httpClient.requests().get(0);
+    assertEquals("GET", request.method());
+    assertEquals("/v2/invoices/zip-requests/zip_1", request.uri().getPath());
+  }
+
+  @Test
+  void invoiceZipRequestCanBeDownloaded() throws Exception {
+    StubHttpClient httpClient = new StubHttpClient();
+    httpClient.enqueueBinary(200, "ZIP-CONTENT".getBytes(StandardCharsets.UTF_8), "application/zip");
+
+    Facturapi sdk = new Facturapi(
+      FacturapiConfig.builder("sk_test")
+        .httpClient(httpClient.client())
+        .build()
+    );
+
+    try (InputStream stream = sdk.invoices().downloadZipRequestStream("zip_1")) {
+      assertEquals("ZIP-CONTENT", new String(stream.readAllBytes(), StandardCharsets.UTF_8));
+    }
+
+    var request = httpClient.requests().get(0);
+    assertEquals("GET", request.method());
+    assertEquals("/v2/invoices/zip-requests/zip_1/zip", request.uri().getPath());
+  }
+
   @Test
   void organizationUploadsAcceptBytes() {
     StubHttpClient httpClient = new StubHttpClient();
@@ -320,4 +508,18 @@ void objectMapperDeserializesCodeEnums() throws Exception {
     assertEquals(TaxType.IEPS, tax.getType());
     assertEquals(TaxFactor.EXENTO, tax.getFactor());
   }
+
+  @Test
+  void objectMapperDeserializesPropertyTaxAccountsAsArrays() throws Exception {
+    var mapper = FacturapiConfig.builder("sk_test").build().getObjectMapper();
+
+    var empty = mapper.readValue("{\"property_tax_account\":[]}", InvoiceItem.class);
+    var accounts = mapper.readValue(
+      "{\"property_tax_account\":[\"0102030405\"]}",
+      InvoiceItem.class
+    );
+
+    assertEquals(List.of(), empty.getPropertyTaxAccounts());
+    assertEquals(List.of("0102030405"), accounts.getPropertyTaxAccounts());
+  }
 }