diff --git a/lib/src/options.dart b/lib/src/options.dart
index 23b6d1f..4d19452 100644
--- a/lib/src/options.dart
+++ b/lib/src/options.dart
@@ -5,13 +5,13 @@ const int defaultHttpPort = 80;
 /// Options to be set on the [Pusher] instance.
 class PusherOptions {
   /// Defines a value indicating whether call to the API are over HTTP or HTTPS.
-  bool _encrypted;
+  bool? _encrypted;
 
   int _port = defaultHttpPort;
 
-  String _cluster;
+  String? _cluster;
 
-  PusherOptions({bool encrypted: false, int port, String cluster}) {
+  PusherOptions({bool encrypted: false, int? port, String? cluster}) {
     this._encrypted = encrypted;
 
     if (port != null) this._port = port;
@@ -22,19 +22,19 @@ class PusherOptions {
   }
 
   /// Indicates whether calls to the Pusher REST API are over HTTP or HTTPS.
-  bool get encrypted => _encrypted;
+  bool? get encrypted => _encrypted;
 
   /// port that the HTTP calls will be made to.
   int get port => _port;
 
-  String get cluster => _cluster;
+  String? get cluster => _cluster;
 
   bool get hasCluster => _cluster != null;
 
   String get host => !hasCluster ? defaultHost : "api-${_cluster}.pusher.com";
 
   String getBaseUrl() {
-    String schema = encrypted ? 'https' : 'http';
+    String schema = encrypted! ? 'https' : 'http';
     String port = _port == 80 ? '' : ":${_port}";
     return "$schema://$host$port";
   }
diff --git a/lib/src/pusher.dart b/lib/src/pusher.dart
index 8f475aa..e058739 100644
--- a/lib/src/pusher.dart
+++ b/lib/src/pusher.dart
@@ -12,15 +12,15 @@ import 'options.dart';
 /// Provides access to functionality within the Pusher service such as Trigger to trigger events
 /// and authenticating subscription requests to private and presence channels.
 class Pusher {
-  String _id;
+  String? _id;
 
-  String _key;
+  String? _key;
 
-  String _secret;
+  String? _secret;
 
-  PusherOptions _options;
+  late PusherOptions _options;
 
-  Pusher(String id, String key, String secret, [PusherOptions options]) {
+  Pusher(String? id, String? key, String? secret, [PusherOptions? options]) {
     this._id = id;
     this._secret = secret;
     this._key = key;
@@ -51,7 +51,7 @@ class Pusher {
   ///      String auth = pusher.authenticate('presence-test_channel',socketId,user);
   ///
   /// Throws a [JsonUnsupportedObjectError] if [User] cannot be serialized
-  String authenticate(String channel, String socketId, [User user]) {
+  String authenticate(String channel, String socketId, [User? user]) {
     validateChannelName(channel);
     validateSocketId(socketId);
     String signature;
@@ -59,12 +59,12 @@ class Pusher {
 
     if (user == null) {
       signature = "$socketId:$channel";
-      token = "$_key:${hmac256(_secret, signature)}";
+      token = "$_key:${hmac256(_secret!, signature)}";
       return json.encode({'auth': token});
     } else {
       String data = json.encode(user.toMap());
       signature = "$socketId:$channel:$data";
-      token = "$_key:${hmac256(_secret, signature)}";
+      token = "$_key:${hmac256(_secret!, signature)}";
       return json.encode({'auth': token, 'channel_data': data});
     }
   }
@@ -84,7 +84,7 @@ class Pusher {
   /// Retrive a list of users that are on a presence channel:
   ///      Response result = await pusher.get('/channels/presence-channel/users');
   Future<Response> get(String resource,
-      [Map<String, String> parameters]) async {
+      [Map<String, String>? parameters]) async {
     parameters = (parameters != null) ? parameters : new Map<String, String>();
     Request request =
         _createAuthenticatedRequest('GET', resource, parameters, null);
@@ -100,7 +100,7 @@ class Pusher {
   /// ## Triggering events
   ///      Response response = await pusher.trigger(['test_channel'],'my_event',data);
   Future<Response> trigger(List<String> channels, String event, Map data,
-      [TriggerOptions options]) {
+      [TriggerOptions? options]) {
     options = options == null ? new TriggerOptions() : options;
     validateListOfChannelNames(channels);
     validateSocketId(options.socketId);
@@ -134,12 +134,12 @@ class Pusher {
   }
 
   Request _createAuthenticatedRequest(String method, String resource,
-      Map<String, String> parameters, TriggerBody body) {
+      Map<String, String>? parameters, TriggerBody? body) {
     resource = resource.startsWith('/') ? resource.substring(1) : resource;
     parameters = parameters == null
         ? new SplayTreeMap()
         : new SplayTreeMap.from(parameters);
-    parameters['auth_key'] = this._key;
+    parameters['auth_key'] = this._key!;
     parameters['auth_timestamp'] = _secondsSinceEpoch().toString();
     parameters['auth_version'] = '1.0';
 
@@ -151,7 +151,7 @@ class Pusher {
     String path = "/apps/${this._id}/$resource";
     String toSign = "$method\n$path\n$queryString";
 
-    String authSignature = hmac256(this._secret, toSign);
+    String authSignature = hmac256(this._secret!, toSign);
 
     Uri uri = Uri.parse(
         "${_options.getBaseUrl()}$path?$queryString&auth_signature=$authSignature");
diff --git a/lib/src/trigger.dart b/lib/src/trigger.dart
index 22bfa92..a2ca297 100644
--- a/lib/src/trigger.dart
+++ b/lib/src/trigger.dart
@@ -5,32 +5,32 @@ import 'validation.dart';
 /// Options to be set on the trigger method.
 class TriggerOptions {
   /// Socket id to be excluded from receiving event.
-  String _socketId;
+  String? _socketId;
 
-  TriggerOptions({String socketId}) {
+  TriggerOptions({String? socketId}) {
     this._socketId = socketId;
   }
 
   /// Socket id to be excluded from receiving event.
-  String get socketId => _socketId;
+  String? get socketId => _socketId;
 }
 
 /// Represents the payload to be sent when triggering events
 class TriggerBody {
   /// The name of the event
-  final String name;
+  final String? name;
 
   /// The event data
-  final String data;
+  final String? data;
 
   /// The channels the event should be triggered on.
-  final List<String> channels;
+  final List<String>? channels;
 
   /// The id of a socket to be excluded from receiving the event.
-  final String socketId;
+  final String? socketId;
 
   TriggerBody({this.name, this.data, this.channels, this.socketId}) {
-    validateListOfChannelNames(this.channels);
+    validateListOfChannelNames(this.channels!);
     validateSocketId(this.socketId);
   }
 
diff --git a/lib/src/user.dart b/lib/src/user.dart
index 9ff5ecf..2e2bedc 100644
--- a/lib/src/user.dart
+++ b/lib/src/user.dart
@@ -6,7 +6,7 @@ class User {
   final String id;
 
   /// Arbitrary additional information about the user.
-  final Map<String, dynamic> info;
+  final Map<String, dynamic>? info;
 
   User(this.id, [this.info]);
 
diff --git a/lib/src/validation.dart b/lib/src/validation.dart
index e238b28..c7acfd2 100644
--- a/lib/src/validation.dart
+++ b/lib/src/validation.dart
@@ -6,7 +6,7 @@ final RegExp channelNameRegex = new RegExp(r'^[A-Za-z0-9_\-=@,.;]+$');
 final int channelNameMaxLength = 164;
 
 /// Validate a socket_id value
-void validateSocketId(String socketId) {
+void validateSocketId(String? socketId) {
   if (socketId != null && socketIdRegex.hasMatch(socketId) == false)
     throw new FormatException(
         "socket_id $socketId was not in the form: ${socketIdRegex.toString()}");
diff --git a/pubspec.yaml b/pubspec.yaml
index 543954c..fea8fef 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,11 +2,11 @@ name: pusher
 description: Pusher HTTP Dart Library
 author: Adao Junior <itsjunnior@gmail.com>
 homepage: https://github.com/adaojunior/pusher
-version: 1.0.0
+version: 2.0.0
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 dependencies:
-  crypto: "^2.0.6"
-  http: "^0.12.0+1"
+  crypto: "^3.0.1"
+  http: "^0.13.2"
 dev_dependencies:
-  test: '^1.5.3'
+  test: '^1.17.3'
diff --git a/test/pusher_test.dart b/test/pusher_test.dart
index 1a4446f..d4ca6cf 100644
--- a/test/pusher_test.dart
+++ b/test/pusher_test.dart
@@ -9,9 +9,9 @@ import 'dart:convert' show json , JsonUnsupportedObjectError;
 import 'dart:io' show Platform;
 import 'utils.dart' as utils;
 
-final String pusherAppId = Platform.environment['PUSHER_APP_ID'];
-final String pusherAppKey = Platform.environment['PUSHER_APP_KEY'];
-final String pusherAppSecret = Platform.environment['PUSHER_APP_SECRET'];
+final String? pusherAppId = Platform.environment['PUSHER_APP_ID'];
+final String? pusherAppKey = Platform.environment['PUSHER_APP_KEY'];
+final String? pusherAppSecret = Platform.environment['PUSHER_APP_SECRET'];
 
 void main() {
   group('PusherOptions', () {
@@ -44,8 +44,8 @@ void main() {
   });
 
   group('TriggerOptions', () {
-    TriggerOptions options;
-    String socketId;
+    late TriggerOptions options;
+    late String socketId;
 
     setUp(() {
       socketId = '444.444';
@@ -58,11 +58,11 @@ void main() {
   });
 
   group('TriggerBody', () {
-    TriggerBody body;
-    String name;
-    String data;
-    List<String> channels;
-    String socketId;
+    late TriggerBody body;
+    late String name;
+    late String data;
+    late List<String> channels;
+    late String socketId;
 
     setUp(() {
       name = 'my-event';
@@ -104,9 +104,9 @@ void main() {
   });
 
   group('Response', () {
-    Response result;
-    int status;
-    String message;
+    late Response result;
+    late int status;
+    late String message;
 
     setUp(() {
       status = 200;
@@ -129,7 +129,7 @@ void main() {
   });
 
   group('Pusher', () {
-    Pusher pusher;
+    late Pusher pusher;
 
     setUp(() {
       pusher = new Pusher(pusherAppId, pusherAppKey, pusherAppSecret);
@@ -227,7 +227,7 @@ void main() {
             "boolean":true,
             "aObjectInstance":instance
           })),
-          throwsA(predicate((e) => e is JsonUnsupportedObjectError))
+          throwsA(predicate((dynamic e) => e is JsonUnsupportedObjectError))
       );
 
     });