diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1d8e0f5..6dae684 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## [0.1.9] - 2026-08-11
+
+* Added an optional authorization protocol version to `ExternalLoginData` to allow the server to select the appropriate authentication flow while preserving compatibility with older clients.
+
 ## [0.1.8] - 2026-02-11
 
 * Added new `invalidTime` error with factory method.
diff --git a/lib/external_login_interface.dart b/lib/external_login_interface.dart
index 77f7fd6..8563d7f 100644
--- a/lib/external_login_interface.dart
+++ b/lib/external_login_interface.dart
@@ -14,7 +14,7 @@ abstract class ExternalLogin {
   /// If is't error, than [ErrorResult.error]
   /// should contains [ExternalLoginErrorData].
   ///
-  /// If [loadAvatar] is `true` than implemention
+  /// If [loadAvatar] is `true` than implementation
   /// should request information about user picture.
   Future<Result<ExternalLoginResult>> login({bool loadAvatar = false});
 
@@ -90,6 +90,13 @@ class ExternalLoginData {
   /// Required by some services, e.g. Apple.
   final String? clientId;
 
+  /// The authorization protocol version used by the client.
+  ///
+  /// A null value means that the client does not specify a protocol version.
+  /// This allows the server to select the appropriate authorization flow
+  /// based on the available information.
+  final int? version;
+
   /// Additional data
   final Map<String, Object?>? data;
 
@@ -100,6 +107,7 @@ class ExternalLoginData {
     this.clientId,
     this.avatarUrl,
     this.email,
+    this.version,
     this.data,
   });
 
@@ -107,7 +115,7 @@ class ExternalLoginData {
   String toString() {
     return 'ExternalLoginResult{userId: $userId, token: $token, '
         'fullName: $fullName, clientId: $clientId, avatarUrl: $avatarUrl, '
-        'email: $email, data: $data}';
+        'email: $email, version: $version, data: $data}';
   }
 }
 
diff --git a/pubspec.yaml b/pubspec.yaml
index 7378055..23fd37f 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: external_login_interface
 description: Interface for external login feature.
-version: 0.1.8
+version: 0.1.9
 homepage: https://github.com/innim/
 repository: https://github.com/Innim/flutter_external_login_interface
 issue_tracker: https://github.com/Innim/flutter_external_login_interface/issues