diff --git a/lib/jmap/core/method/response/query_response.dart b/lib/jmap/core/method/response/query_response.dart
index f4fa149..06bb232 100644
--- a/lib/jmap/core/method/response/query_response.dart
+++ b/lib/jmap/core/method/response/query_response.dart
@@ -9,8 +9,8 @@ abstract class QueryResponse extends ResponseRequiringAccountId {
   final bool canCalculateChanges;
   final UnsignedInt position;
   final Set<Id> ids;
-  final UnsignedInt total;
-  final UnsignedInt limit;
+  final UnsignedInt? total;
+  final UnsignedInt? limit;
 
   QueryResponse(
     AccountId accountId,
diff --git a/lib/jmap/identities/get/get_identity_method.dart b/lib/jmap/identities/get/get_identity_method.dart
index 9fc408b..c40c649 100644
--- a/lib/jmap/identities/get/get_identity_method.dart
+++ b/lib/jmap/identities/get/get_identity_method.dart
@@ -37,5 +37,6 @@ class GetIdentityMethod extends GetMethod {
 
   factory GetIdentityMethod.fromJson(Map<String, dynamic> json) => _$GetIdentityMethodFromJson(json);
 
+  @override
   Map<String, dynamic> toJson() => _$GetIdentityMethodToJson(this);
 }
\ No newline at end of file
diff --git a/lib/jmap/identities/set/set_identity_method.dart b/lib/jmap/identities/set/set_identity_method.dart
index 044da35..0fb0d56 100644
--- a/lib/jmap/identities/set/set_identity_method.dart
+++ b/lib/jmap/identities/set/set_identity_method.dart
@@ -43,7 +43,7 @@ class SetIdentityMethod extends SetMethod<Identity> {
     writeNotNull('update', update
       ?.map((id, update) => SetMethodPropertiesConverter().fromMapIdToJson(id, update.toJson())));
     writeNotNull('destroy', destroy
-      ?.map((destroyId) => IdConverter().toJson(destroyId)).toList());
+      ?.map((destroyId) => const IdConverter().toJson(destroyId)).toList());
 
     return val;
   }
diff --git a/lib/jmap/jmap_request.dart b/lib/jmap/jmap_request.dart
index 967ec52..4e0b720 100644
--- a/lib/jmap/jmap_request.dart
+++ b/lib/jmap/jmap_request.dart
@@ -1,4 +1,5 @@
 import 'package:built_collection/built_collection.dart';
+import 'package:dio/dio.dart';
 import 'package:jmap_dart_client/http/http_client.dart';
 import 'package:jmap_dart_client/jmap/core/request/reference_path.dart';
 import 'package:jmap_dart_client/jmap/core/request/result_reference.dart';
@@ -20,14 +21,18 @@ class JmapRequest {
   RequestObject? _requestObject;
   RequestObject? get requestObject => _requestObject;
 
-  Future<ResponseObject> execute() async {
+  Future<ResponseObject> execute({CancelToken? cancelToken}) async {
     _requestObject = (RequestObject.builder()
         ..usings(_capabilities.asSet())
         ..methodCalls(_invocations.values.toList()))
       .build();
 
-    return _httpClient.post('', data: _requestObject?.toJson())
-      .then((value) => extractData(value))
+    return _httpClient.post(
+      '',
+      data: _requestObject?.toJson(),
+      cancelToken: cancelToken
+    )
+      .then(extractData)
       .catchError((error) => throw error);
   }
 
diff --git a/lib/jmap/mail/email/changes/changes_email_response.g.dart b/lib/jmap/mail/email/changes/changes_email_response.g.dart
index 1b494cd..038f814 100644
--- a/lib/jmap/mail/email/changes/changes_email_response.g.dart
+++ b/lib/jmap/mail/email/changes/changes_email_response.g.dart
@@ -22,16 +22,4 @@ ChangesEmailResponse _$ChangesEmailResponseFromJson(Map<String, dynamic> json) {
         .map((e) => const IdConverter().fromJson(e as String))
         .toSet(),
   );
-}
-
-Map<String, dynamic> _$ChangesEmailResponseToJson(
-        ChangesEmailResponse instance) =>
-    <String, dynamic>{
-      'accountId': const AccountIdConverter().toJson(instance.accountId),
-      'oldState': const StateConverter().toJson(instance.oldState),
-      'newState': const StateConverter().toJson(instance.newState),
-      'hasMoreChanges': instance.hasMoreChanges,
-      'created': instance.created.map(const IdConverter().toJson).toList(),
-      'updated': instance.updated.map(const IdConverter().toJson).toList(),
-      'destroyed': instance.destroyed.map(const IdConverter().toJson).toList(),
-    };
+}
\ No newline at end of file
diff --git a/lib/jmap/mail/email/email_body_value.dart b/lib/jmap/mail/email/email_body_value.dart
index 109cab1..4413d9f 100644
--- a/lib/jmap/mail/email/email_body_value.dart
+++ b/lib/jmap/mail/email/email_body_value.dart
@@ -1,20 +1,75 @@
 import 'package:equatable/equatable.dart';
-import 'package:json_annotation/json_annotation.dart';
+import 'package:jmap_dart_client/http/converter/individual_header_identifier_converter.dart';
+import 'package:jmap_dart_client/jmap/mail/email/individual_header_identifier.dart';
 
-part 'email_body_value.g.dart';
-
-@JsonSerializable()
 class EmailBodyValue with EquatableMixin {
   final String value;
   final bool isEncodingProblem;
   final bool isTruncated;
+  final Map<IndividualHeaderIdentifier, String?>? acceptLanguageHeader;
+  final Map<IndividualHeaderIdentifier, String?>? contentLanguageHeader;
+
+  EmailBodyValue({
+    required this.value,
+    required this.isEncodingProblem,
+    required this.isTruncated,
+    this.acceptLanguageHeader,
+    this.contentLanguageHeader
+  });
+
+  factory EmailBodyValue.fromJson(Map<String, dynamic> json) {
+    return EmailBodyValue(
+      value: json['value'] as String,
+      isEncodingProblem: json['isEncodingProblem'] as bool,
+      isTruncated: json['isTruncated'] as bool,
+      acceptLanguageHeader: IndividualHeaderIdentifierNullableConverter()
+        .parseEntry(
+          IndividualHeaderIdentifier.acceptLanguageHeader.value,
+          json[IndividualHeaderIdentifier.acceptLanguageHeader.value] as String?
+        ),
+      contentLanguageHeader: IndividualHeaderIdentifierNullableConverter()
+        .parseEntry(
+          IndividualHeaderIdentifier.contentLanguageHeader.value,
+          json[IndividualHeaderIdentifier.contentLanguageHeader.value] as String?
+        ),
+    );
+  }
 
-  EmailBodyValue(this.value, this.isEncodingProblem, this.isTruncated);
+  Map<String, dynamic> toJson() {
+    final val = <String, dynamic>{};
 
-  factory EmailBodyValue.fromJson(Map<String, dynamic> json) => _$EmailBodyValueFromJson(json);
+    void writeNotNull(String key, dynamic value) {
+      if (value != null) {
+        val[key] = value;
+      }
+    }
 
-  Map<String, dynamic> toJson() => _$EmailBodyValueToJson(this);
+    writeNotNull('value', value);
+    writeNotNull('isEncodingProblem', isEncodingProblem);
+    writeNotNull('isTruncated', isTruncated);
+    writeNotNull(
+      IndividualHeaderIdentifier.acceptLanguageHeader.value,
+      IndividualHeaderIdentifierNullableConverter().toJson(
+        acceptLanguageHeader,
+        IndividualHeaderIdentifier.acceptLanguageHeader
+      )
+    );
+    writeNotNull(
+      IndividualHeaderIdentifier.contentLanguageHeader.value,
+      IndividualHeaderIdentifierNullableConverter().toJson(
+        contentLanguageHeader,
+        IndividualHeaderIdentifier.contentLanguageHeader
+      )
+    );
+    return val;
+  }
 
   @override
-  List<Object?> get props => [value, isEncodingProblem, isTruncated];
+  List<Object?> get props => [
+    value,
+    isEncodingProblem,
+    isTruncated,
+    acceptLanguageHeader,
+    contentLanguageHeader,
+  ];
 }
\ No newline at end of file
diff --git a/lib/jmap/mail/email/email_body_value.g.dart b/lib/jmap/mail/email/email_body_value.g.dart
deleted file mode 100644
index 38b30ee..0000000
--- a/lib/jmap/mail/email/email_body_value.g.dart
+++ /dev/null
@@ -1,22 +0,0 @@
-// GENERATED CODE - DO NOT MODIFY BY HAND
-
-part of 'email_body_value.dart';
-
-// **************************************************************************
-// JsonSerializableGenerator
-// **************************************************************************
-
-EmailBodyValue _$EmailBodyValueFromJson(Map<String, dynamic> json) {
-  return EmailBodyValue(
-    json['value'] as String,
-    json['isEncodingProblem'] as bool,
-    json['isTruncated'] as bool,
-  );
-}
-
-Map<String, dynamic> _$EmailBodyValueToJson(EmailBodyValue instance) =>
-    <String, dynamic>{
-      'value': instance.value,
-      'isEncodingProblem': instance.isEncodingProblem,
-      'isTruncated': instance.isTruncated,
-    };
diff --git a/lib/jmap/mail/email/individual_header_identifier.dart b/lib/jmap/mail/email/individual_header_identifier.dart
index b2ed503..12b6ace 100644
--- a/lib/jmap/mail/email/individual_header_identifier.dart
+++ b/lib/jmap/mail/email/individual_header_identifier.dart
@@ -4,6 +4,8 @@ class IndividualHeaderIdentifier with EquatableMixin {
   static final headerUserAgent = IndividualHeaderIdentifier('header:User-Agent:asText');
   static final headerMdn = IndividualHeaderIdentifier('header:Disposition-Notification-To:asText');
   static final headerCalendarEvent = IndividualHeaderIdentifier('header:X-MEETING-UID:asText');
+  static final acceptLanguageHeader = IndividualHeaderIdentifier('header:Accept-Language:asText');
+  static final contentLanguageHeader = IndividualHeaderIdentifier('header:Content-Language:asText');
 
   final String value;
 
diff --git a/lib/jmap/mail/email/query/query_email_response.dart b/lib/jmap/mail/email/query/query_email_response.dart
index 08fe06b..649815f 100644
--- a/lib/jmap/mail/email/query/query_email_response.dart
+++ b/lib/jmap/mail/email/query/query_email_response.dart
@@ -2,6 +2,7 @@ import 'package:jmap_dart_client/http/converter/account_id_converter.dart';
 import 'package:jmap_dart_client/http/converter/id_converter.dart';
 import 'package:jmap_dart_client/http/converter/state_converter.dart';
 import 'package:jmap_dart_client/http/converter/unsigned_int_converter.dart';
+import 'package:jmap_dart_client/http/converter/unsigned_int_nullable_converter.dart';
 import 'package:jmap_dart_client/jmap/account_id.dart';
 import 'package:jmap_dart_client/jmap/core/id.dart';
 import 'package:jmap_dart_client/jmap/core/method/response/query_response.dart';
@@ -24,8 +25,8 @@ class QueryEmailResponse extends QueryResponse {
     bool canCalculateChanges,
     UnsignedInt position,
     Set<Id> ids,
-    UnsignedInt total,
-    UnsignedInt limit,
+    UnsignedInt? total,
+    UnsignedInt? limit,
   ) : super(accountId, queryState, canCalculateChanges, position, ids, total, limit);
 
   factory QueryEmailResponse.fromJson(Map<String, dynamic> json) => _$QueryEmailResponseFromJson(json);
diff --git a/lib/jmap/mail/email/query/query_email_response.g.dart b/lib/jmap/mail/email/query/query_email_response.g.dart
index 4f60872..98187bf 100644
--- a/lib/jmap/mail/email/query/query_email_response.g.dart
+++ b/lib/jmap/mail/email/query/query_email_response.g.dart
@@ -15,8 +15,8 @@ QueryEmailResponse _$QueryEmailResponseFromJson(Map<String, dynamic> json) {
     (json['ids'] as List<dynamic>)
         .map((e) => const IdConverter().fromJson(e as String))
         .toSet(),
-    const UnsignedIntConverter().fromJson(json['total'] as int),
-    const UnsignedIntConverter().fromJson(json['limit'] as int),
+    const UnsignedIntNullableConverter().fromJson(json['total'] as int?),
+    const UnsignedIntNullableConverter().fromJson(json['limit'] as int?),
   );
 }
 
@@ -27,6 +27,6 @@ Map<String, dynamic> _$QueryEmailResponseToJson(QueryEmailResponse instance) =>
       'canCalculateChanges': instance.canCalculateChanges,
       'position': const UnsignedIntConverter().toJson(instance.position),
       'ids': instance.ids.map(const IdConverter().toJson).toList(),
-      'total': const UnsignedIntConverter().toJson(instance.total),
-      'limit': const UnsignedIntConverter().toJson(instance.limit),
+      'total': const UnsignedIntNullableConverter().toJson(instance.total),
+      'limit': const UnsignedIntNullableConverter().toJson(instance.limit),
     };
diff --git a/lib/jmap/mail/email/set/set_email_method.dart b/lib/jmap/mail/email/set/set_email_method.dart
index c190ce7..185c95b 100644
--- a/lib/jmap/mail/email/set/set_email_method.dart
+++ b/lib/jmap/mail/email/set/set_email_method.dart
@@ -39,7 +39,7 @@ class SetEmailMethod extends SetMethod<Email> {
       ?.map((id, update) => SetMethodPropertiesConverter()
         .fromMapIdToJson(id, update.toJson())));
     writeNotNull('destroy', destroy
-      ?.map((destroyId) => IdConverter()
+      ?.map((destroyId) => const IdConverter()
         .toJson(destroyId)).toList());
     
     return val;
diff --git a/lib/jmap/mail/email/submission/set/set_email_submission_method.dart b/lib/jmap/mail/email/submission/set/set_email_submission_method.dart
index 82820b3..7723691 100644
--- a/lib/jmap/mail/email/submission/set/set_email_submission_method.dart
+++ b/lib/jmap/mail/email/submission/set/set_email_submission_method.dart
@@ -45,13 +45,13 @@ class SetEmailSubmissionMethod extends SetMethod<EmailSubmission> with OptionalO
         ?.map((id, update) => SetMethodPropertiesConverter()
         .fromMapIdToJson(id, update.toJson())));
     writeNotNull('destroy', destroy
-        ?.map((destroyId) => IdConverter()
+        ?.map((destroyId) => const IdConverter()
         .toJson(destroyId)).toList());
     writeNotNull('onSuccessUpdateEmail', onSuccessUpdateEmail
         ?.map((id, update) => SetMethodPropertiesConverter()
         .fromMapEmailSubmissionIdToJson(id, update)));
     writeNotNull('onSuccessDestroyEmail', onSuccessDestroyEmail
-        ?.map((destroyId) => ReferencesEmailSubmissionIdConverter()
+        ?.map((destroyId) => const ReferencesEmailSubmissionIdConverter()
         .toJson(destroyId)).toList());
 
     return val;
@@ -66,9 +66,7 @@ mixin OptionalOnSuccessUpdateEmail {
   Map<EmailSubmissionId, PatchObject>? onSuccessUpdateEmail;
 
   void addOnSuccessUpdateEmail(Map<EmailSubmissionId, PatchObject> values) {
-    if (onSuccessUpdateEmail == null) {
-      onSuccessUpdateEmail = Map<EmailSubmissionId, PatchObject>();
-    }
+    onSuccessUpdateEmail ??= <EmailSubmissionId, PatchObject>{};
     onSuccessUpdateEmail?.addAll(values);
   }
 }
@@ -78,9 +76,7 @@ mixin OptionalOnSuccessDestroyEmail {
   Set<EmailSubmissionId>? onSuccessDestroyEmail;
 
   void addOnSuccessDestroyEmail(Set<EmailSubmissionId> values) {
-    if (onSuccessDestroyEmail == null) {
-      onSuccessDestroyEmail = Set();
-    }
+    onSuccessDestroyEmail ??= <EmailSubmissionId>{};
     onSuccessDestroyEmail?.addAll(values);
   }
 }
\ No newline at end of file
diff --git a/lib/jmap/mail/mailbox/get/get_mailbox_method.dart b/lib/jmap/mail/mailbox/get/get_mailbox_method.dart
index ae9fbd3..0a35847 100644
--- a/lib/jmap/mail/mailbox/get/get_mailbox_method.dart
+++ b/lib/jmap/mail/mailbox/get/get_mailbox_method.dart
@@ -37,5 +37,6 @@ class GetMailboxMethod extends GetMethod {
 
   factory GetMailboxMethod.fromJson(Map<String, dynamic> json) => _$GetMailboxMethodFromJson(json);
 
+  @override
   Map<String, dynamic> toJson() => _$GetMailboxMethodToJson(this);
 }
\ No newline at end of file
diff --git a/lib/jmap/mail/mailbox/mailbox_rights.dart b/lib/jmap/mail/mailbox/mailbox_rights.dart
index 7352583..a4ee9a0 100644
--- a/lib/jmap/mail/mailbox/mailbox_rights.dart
+++ b/lib/jmap/mail/mailbox/mailbox_rights.dart
@@ -30,6 +30,8 @@ class MailboxRights with EquatableMixin {
     return _$MailboxRightsFromJson(json);
   }
 
+  Map<String, dynamic> toJson() => _$MailboxRightsToJson(this);
+
   @override
   List<Object?> get props => [mayReadItems, mayAddItems, mayRemoveItems, maySetSeen,
     maySetKeywords, mayCreateChild, mayRename, mayDelete, maySubmit];
diff --git a/lib/jmap/mail/mailbox/query/query_mailbox_response.dart b/lib/jmap/mail/mailbox/query/query_mailbox_response.dart
index 3aafcbe..a9cd133 100644
--- a/lib/jmap/mail/mailbox/query/query_mailbox_response.dart
+++ b/lib/jmap/mail/mailbox/query/query_mailbox_response.dart
@@ -2,6 +2,7 @@ import 'package:jmap_dart_client/http/converter/account_id_converter.dart';
 import 'package:jmap_dart_client/http/converter/id_converter.dart';
 import 'package:jmap_dart_client/http/converter/state_converter.dart';
 import 'package:jmap_dart_client/http/converter/unsigned_int_converter.dart';
+import 'package:jmap_dart_client/http/converter/unsigned_int_nullable_converter.dart';
 import 'package:jmap_dart_client/jmap/account_id.dart';
 import 'package:jmap_dart_client/jmap/core/id.dart';
 import 'package:jmap_dart_client/jmap/core/method/response/query_response.dart';
@@ -24,8 +25,8 @@ class QueryMailboxResponse extends QueryResponse {
     bool canCalculateChanges,
     UnsignedInt position,
     Set<Id> ids,
-    UnsignedInt total,
-    UnsignedInt limit,
+    UnsignedInt? total,
+    UnsignedInt? limit,
   ) : super(accountId, queryState, canCalculateChanges, position, ids, total, limit);
 
   factory QueryMailboxResponse.fromJson(Map<String, dynamic> json) => _$QueryMailboxResponseFromJson(json);
diff --git a/lib/jmap/mail/mailbox/query/query_mailbox_response.g.dart b/lib/jmap/mail/mailbox/query/query_mailbox_response.g.dart
index c924f4a..e12f920 100644
--- a/lib/jmap/mail/mailbox/query/query_mailbox_response.g.dart
+++ b/lib/jmap/mail/mailbox/query/query_mailbox_response.g.dart
@@ -16,8 +16,8 @@ QueryMailboxResponse _$QueryMailboxResponseFromJson(
       (json['ids'] as List<dynamic>)
           .map((e) => const IdConverter().fromJson(e as String))
           .toSet(),
-      const UnsignedIntConverter().fromJson(json['total'] as int),
-      const UnsignedIntConverter().fromJson(json['limit'] as int),
+      const UnsignedIntNullableConverter().fromJson(json['total'] as int?),
+      const UnsignedIntNullableConverter().fromJson(json['limit'] as int?),
     );
 
 Map<String, dynamic> _$QueryMailboxResponseToJson(
@@ -28,6 +28,6 @@ Map<String, dynamic> _$QueryMailboxResponseToJson(
       'canCalculateChanges': instance.canCalculateChanges,
       'position': const UnsignedIntConverter().toJson(instance.position),
       'ids': instance.ids.map(const IdConverter().toJson).toList(),
-      'total': const UnsignedIntConverter().toJson(instance.total),
-      'limit': const UnsignedIntConverter().toJson(instance.limit),
+      'total': const UnsignedIntNullableConverter().toJson(instance.total),
+      'limit': const UnsignedIntNullableConverter().toJson(instance.limit),
     };
diff --git a/lib/jmap/mail/mailbox/set/set_mailbox_method.dart b/lib/jmap/mail/mailbox/set/set_mailbox_method.dart
index b59463e..bccbefa 100644
--- a/lib/jmap/mail/mailbox/set/set_mailbox_method.dart
+++ b/lib/jmap/mail/mailbox/set/set_mailbox_method.dart
@@ -38,7 +38,7 @@ class SetMailboxMethod extends SetMethod<Mailbox> with OptionalOnDestroyRemoveEm
     writeNotNull('update', update
       ?.map((id, update) => SetMethodPropertiesConverter().fromMapIdToJson(id, update.toJson())));
     writeNotNull('destroy', destroy
-      ?.map((destroyId) => IdConverter().toJson(destroyId)).toList());
+      ?.map((destroyId) => const IdConverter().toJson(destroyId)).toList());
     writeNotNull('onDestroyRemoveEmails', onDestroyRemoveEmails);
 
     return val;
diff --git a/lib/jmap/mail/vacation/get/get_vacation_method.dart b/lib/jmap/mail/vacation/get/get_vacation_method.dart
index d868f26..587ef45 100644
--- a/lib/jmap/mail/vacation/get/get_vacation_method.dart
+++ b/lib/jmap/mail/vacation/get/get_vacation_method.dart
@@ -37,5 +37,6 @@ class GetVacationMethod extends GetMethod {
   factory GetVacationMethod.fromJson(Map<String, dynamic> json) =>
       _$GetVacationMethodFromJson(json);
 
+  @override
   Map<String, dynamic> toJson() => _$GetVacationMethodToJson(this);
 }
\ No newline at end of file
diff --git a/lib/jmap/mdn/send/mdn_send_response.dart b/lib/jmap/mdn/send/mdn_send_response.dart
index 8fe8b4b..823e116 100644
--- a/lib/jmap/mdn/send/mdn_send_response.dart
+++ b/lib/jmap/mdn/send/mdn_send_response.dart
@@ -17,11 +17,11 @@ class MDNSendResponse extends SendResponse<MDN> {
       const AccountIdConverter().fromJson(json['accountId'] as String),
       sent: (json['sent'] as Map<String, dynamic>?)
           ?.map((key, value) => MapEntry(
-              IdConverter().fromJson(key),
+              const IdConverter().fromJson(key),
               MDN.fromJson(value as Map<String, dynamic>))),
       notSent: (json['notSent'] as Map<String, dynamic>?)
           ?.map((key, value) => MapEntry(
-              IdConverter().fromJson(key),
+              const IdConverter().fromJson(key),
               SetError.fromJson(value))),
     );
   }
diff --git a/lib/jmap/push/get/get_push_subscription_method.dart b/lib/jmap/push/get/get_push_subscription_method.dart
index 1b52ead..7923533 100644
--- a/lib/jmap/push/get/get_push_subscription_method.dart
+++ b/lib/jmap/push/get/get_push_subscription_method.dart
@@ -27,5 +27,6 @@ class GetPushSubscriptionMethod extends GetMethodNoNeedAccountId {
 
   factory GetPushSubscriptionMethod.fromJson(Map<String, dynamic> json) => _$GetPushSubscriptionMethodFromJson(json);
 
+  @override
   Map<String, dynamic> toJson() => _$GetPushSubscriptionMethodToJson(this);
 }
\ No newline at end of file
diff --git a/lib/jmap/push/set/set_push_subscription_method.dart b/lib/jmap/push/set/set_push_subscription_method.dart
index 10610e1..9fa4f52 100644
--- a/lib/jmap/push/set/set_push_subscription_method.dart
+++ b/lib/jmap/push/set/set_push_subscription_method.dart
@@ -31,7 +31,7 @@ class SetPushSubscriptionMethod extends SetMethodNoNeedAccountId<PushSubscriptio
     writeNotNull('update', update
       ?.map((id, update) => SetMethodPropertiesConverter().fromMapIdToJson(id, update.toJson())));
     writeNotNull('destroy', destroy
-      ?.map((destroyId) => IdConverter().toJson(destroyId)).toList());
+      ?.map((destroyId) => const IdConverter().toJson(destroyId)).toList());
 
     return val;
   }
diff --git a/lib/jmap/push/set/set_push_subscription_response.dart b/lib/jmap/push/set/set_push_subscription_response.dart
index 9943fdc..f62f128 100644
--- a/lib/jmap/push/set/set_push_subscription_response.dart
+++ b/lib/jmap/push/set/set_push_subscription_response.dart
@@ -25,25 +25,25 @@ class SetPushSubscriptionResponse extends SetResponseNoAccount<PushSubscription>
     return SetPushSubscriptionResponse(
       created: (json['created'] as Map<String, dynamic>?)
         ?.map((key, value) => MapEntry(
-            IdConverter().fromJson(key),
+            const IdConverter().fromJson(key),
             PushSubscription.fromJson(value as Map<String, dynamic>))),
       updated: (json['updated'] as Map<String, dynamic>?)
         ?.map((key, value) => MapEntry(
-            IdConverter().fromJson(key),
+            const IdConverter().fromJson(key),
             value != null ? PushSubscription.fromJson(value as Map<String, dynamic>) : null)),
       destroyed: (json['destroyed'] as List<dynamic>?)
-        ?.map((id) => IdConverter().fromJson(id)).toSet(),
+        ?.map((id) => const IdConverter().fromJson(id)).toSet(),
       notCreated: (json['notCreated'] as Map<String, dynamic>?)
         ?.map((key, value) => MapEntry(
-            IdConverter().fromJson(key),
+            const IdConverter().fromJson(key),
             SetError.fromJson(value))),
       notUpdated: (json['notUpdated'] as Map<String, dynamic>?)
         ?.map((key, value) => MapEntry(
-            IdConverter().fromJson(key),
+            const IdConverter().fromJson(key),
             SetError.fromJson(value))),
       notDestroyed: (json['notDestroyed'] as Map<String, dynamic>?)
         ?.map((key, value) => MapEntry(
-            IdConverter().fromJson(key),
+            const IdConverter().fromJson(key),
             SetError.fromJson(value))),
     );
   }
diff --git a/lib/jmap/push/state_change.dart b/lib/jmap/push/state_change.dart
index ebaf676..03ef325 100644
--- a/lib/jmap/push/state_change.dart
+++ b/lib/jmap/push/state_change.dart
@@ -12,9 +12,7 @@ class StateChange with EquatableMixin {
   StateChange(this.type, this.changed);
 
   factory StateChange.fromJson(Map<String, dynamic> json, {TypeStateConverter? converter}) {
-    if (converter == null) {
-      converter = TypeStateConverter.defaultConverter;
-    }
+    converter ??= TypeStateConverter.defaultConverter;
     return StateChange(
         json['@type'] as String,
         (json['changed'] as Map<String, dynamic>).map((key, value) => converter!.convert(key, value)),
diff --git a/lib/jmap/quotas/get/get_quota_method.dart b/lib/jmap/quotas/get/get_quota_method.dart
index 1840c77..e09d2da 100644
--- a/lib/jmap/quotas/get/get_quota_method.dart
+++ b/lib/jmap/quotas/get/get_quota_method.dart
@@ -32,5 +32,6 @@ class GetQuotaMethod extends GetMethod {
 
   factory GetQuotaMethod.fromJson(Map<String, dynamic> json) => _$GetQuotaMethodFromJson(json);
 
+  @override
   Map<String, dynamic> toJson() => _$GetQuotaMethodToJson(this);
 }
\ No newline at end of file
diff --git a/lib/util/options_extensions.dart b/lib/util/options_extensions.dart
index f20e898..7c252cd 100644
--- a/lib/util/options_extensions.dart
+++ b/lib/util/options_extensions.dart
@@ -2,10 +2,10 @@ import 'package:dio/dio.dart';
 
 extension OptionsExtension on Options {
   Options appendHeaders(Map<String, dynamic> additionalHeaders) {
-    if (this.headers != null) {
-      this.headers?.addAll(additionalHeaders);
+    if (headers != null) {
+      headers?.addAll(additionalHeaders);
     } else {
-      this.headers = additionalHeaders;
+      headers = additionalHeaders;
     }
     return this;
   }
diff --git a/lib/util/util.dart b/lib/util/util.dart
index 6a35e6c..a4b0d79 100644
--- a/lib/util/util.dart
+++ b/lib/util/util.dart
@@ -1,4 +1,6 @@
 Iterable<int> get positiveIntegers sync* {
   int i = 0;
-  while (true) yield i++;
+  while (true) {
+    yield i++;
+  }
 }
\ No newline at end of file
diff --git a/test/jmap/core/session/session_test.dart b/test/jmap/core/session/session_test.dart
index e10e7d5..cdda03a 100644
--- a/test/jmap/core/session/session_test.dart
+++ b/test/jmap/core/session/session_test.dart
@@ -25,7 +25,7 @@ import 'test_capability.dart';
 void main() {
   group('get session with default capabilities', () {
     test('get should parsing correctly session', () {
-      final sessionString = '''{
+      const sessionString = '''{
         "capabilities": {
           "urn:ietf:params:jmap:submission": {
             "maxDelayedSend": 0,
@@ -170,8 +170,8 @@ void main() {
             supportsPush: true,
             url: Uri.parse('ws://domain.com/jmap/ws')
           ),
-          CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(Map<String, dynamic>()),
-          CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(Map<String, dynamic>()),
+          CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+          CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
           CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
           CapabilityIdentifier.jmapMdn: MdnCapability()
         },
@@ -206,8 +206,8 @@ void main() {
                 emailQuerySortOptions: {"receivedAt", "sentAt", "size", "from", "to", "subject"},
                 mayCreateTopLevelMailbox: true
               ),
-              CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(Map<String, dynamic>()),
-              CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(Map<String, dynamic>()),
+              CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+              CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
               CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
               CapabilityIdentifier.jmapMdn: MdnCapability()
             }
@@ -238,7 +238,7 @@ void main() {
     });
 
     test('get should parsing correctly session with some limit capabilities', () {
-      final sessionString = '''{
+      const sessionString = '''{
         "capabilities": {
           "urn:ietf:params:jmap:submission": {
             "maxDelayedSend": 0,
@@ -404,7 +404,7 @@ void main() {
     });
 
     test('get should parsing correctly session with some capabilities miss property', () {
-      final sessionString = '''{
+      const sessionString = '''{
         "capabilities": {
           "urn:ietf:params:jmap:submission": {
             "maxDelayedSend": 0,
@@ -550,7 +550,7 @@ void main() {
 
   group('get session with unknown capability', () {
     test('get should parsing correctly session with default converter', () {
-      final sessionString = '''{
+      const sessionString = '''{
         "capabilities": {
           "urn:tmail:custom:params:mailbox": {
             "param1": 1,
@@ -705,8 +705,8 @@ void main() {
               supportsPush: true,
               url: Uri.parse('ws://domain.com/jmap/ws')
             ),
-            CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(Map<String, dynamic>()),
-            CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(Map<String, dynamic>()),
+            CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+            CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
             CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
             CapabilityIdentifier.jmapMdn: MdnCapability()
           },
@@ -742,8 +742,8 @@ void main() {
                     emailQuerySortOptions: {"receivedAt", "sentAt", "size", "from", "to", "subject"},
                     mayCreateTopLevelMailbox: true
                   ),
-                  CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(Map<String, dynamic>()),
-                  CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(Map<String, dynamic>()),
+                  CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+                  CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
                   CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
                   CapabilityIdentifier.jmapMdn: MdnCapability()
                 }
@@ -780,7 +780,7 @@ void main() {
 
   group('get session with custom capability', () {
     test('get should parsing correctly with relevant custom converter', () {
-      final sessionString = '''{
+      const sessionString = '''{
         "capabilities": {
           "urn:test:tmail:params:custom": {
             "testParam1": 100,
@@ -943,8 +943,8 @@ void main() {
               supportsPush: true,
               url: Uri.parse('ws://domain.com/jmap/ws')
             ),
-            CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(Map<String, dynamic>()),
-            CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(Map<String, dynamic>()),
+            CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+            CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
             CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
             CapabilityIdentifier.jmapMdn: MdnCapability()
           },
@@ -980,8 +980,8 @@ void main() {
                     emailQuerySortOptions: {"receivedAt", "sentAt", "size", "from", "to", "subject"},
                     mayCreateTopLevelMailbox: true
                   ),
-                  CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(Map<String, dynamic>()),
-                  CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(Map<String, dynamic>()),
+                  CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+                  CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
                   CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
                   CapabilityIdentifier.jmapMdn: MdnCapability()
                 }
@@ -1020,7 +1020,7 @@ void main() {
 
   group('get session with empty capability', () {
     test('get should ignore parsing empty capability properties', () {
-      final sessionString = '''{
+      const sessionString = '''{
         "capabilities": {
           "urn:ietf:params:jmap:submission": {
             "maxDelayedSend": 0,
@@ -1162,7 +1162,7 @@ void main() {
 
   group('get session for CYRUS server', () {
     test('get should parsing correctly session', () {
-      final sessionString = '''
+      const sessionString = '''
       {
         "username": "example",
         "apiUrl": "/jmap/",
@@ -1305,7 +1305,7 @@ void main() {
             CapabilityIdentifier.jmapSubmission: SubmissionCapability(),
             CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
             CapabilityIdentifier.jmapMdn: MdnCapability(),
-            CapabilityIdentifier(Uri.parse('https://cyrusimap.org/ns/jmap/sieve')): DefaultCapability(Map<String, dynamic>()),
+            CapabilityIdentifier(Uri.parse('https://cyrusimap.org/ns/jmap/sieve')): DefaultCapability(<String, dynamic>{}),
           },
           {
             AccountId(Id('example')): Account(
diff --git a/test/jmap/core/utc_date_converter_test.dart b/test/jmap/core/utc_date_converter_test.dart
index 364b8a2..7745d65 100644
--- a/test/jmap/core/utc_date_converter_test.dart
+++ b/test/jmap/core/utc_date_converter_test.dart
@@ -6,10 +6,10 @@ import 'package:jmap_dart_client/jmap/core/utc_date.dart';
 
 void main() {
 
-  final utcDateStringTest = '2021-10-04T04:39:56.000Z';
+  const utcDateStringTest = '2021-10-04T04:39:56.000Z';
   final expectUTCDate = UTCDate(DateTime.parse('2021-10-04T04:39:56.000Z').toUtc());
   final testUTCDate = UTCDate(DateTime.parse('2021-10-04T04:39:56.000Z').toUtc());
-  final expectUTCDateString = '2021-10-04T04:39:56.000Z';
+  const expectUTCDateString = '2021-10-04T04:39:56.000Z';
 
   group('UTCDateConverter', () {
     test('should return UTCDate when receive a properly formatted json', () {
diff --git a/test/jmap/email/email_object_test.dart b/test/jmap/email/email_object_test.dart
index da71101..0925bca 100644
--- a/test/jmap/email/email_object_test.dart
+++ b/test/jmap/email/email_object_test.dart
@@ -155,9 +155,9 @@ void main() {
         },
         bodyValues: {
           PartId('2'): EmailBodyValue(
-            'Dear, I update my last week activities. Thanks and BRs',
-            false,
-            false
+            value: 'Dear, I update my last week activities. Thanks and BRs',
+            isEncodingProblem: false,
+            isTruncated: false
           )
         },
         preview: 'Dear, I update my last week activities. Thanks and BRs',
@@ -330,9 +330,9 @@ void main() {
         },
         bodyValues: {
           PartId('2'): EmailBodyValue(
-            'Dear, I update my last week activities. Thanks and BRs',
-            false,
-            false
+            value: 'Dear, I update my last week activities. Thanks and BRs',
+            isEncodingProblem: false,
+            isTruncated: false
           )
         },
         preview: 'Dear, I update my last week activities. Thanks and BRs',
@@ -503,9 +503,9 @@ void main() {
         },
         bodyValues: {
           PartId('2'): EmailBodyValue(
-            'Dear, I update my last week activities. Thanks and BRs',
-            false,
-            false
+            value: 'Dear, I update my last week activities. Thanks and BRs',
+            isEncodingProblem: false,
+            isTruncated: false
           )
         },
         preview: 'Dear, I update my last week activities. Thanks and BRs',
diff --git a/test/jmap/email/query/query_with_operator_emails_test.dart b/test/jmap/email/query/query_with_operator_emails_test.dart
index 07beb03..97ab8ed 100644
--- a/test/jmap/email/query/query_with_operator_emails_test.dart
+++ b/test/jmap/email/query/query_with_operator_emails_test.dart
@@ -244,10 +244,10 @@ void main() {
         })
         ..addFilters(LogicFilterOperator(
             Operator.OR,
-            Set<Filter>.from([
+            <Filter>{
               EmailFilterCondition(hasKeyword: "music"),
               EmailFilterCondition(hasKeyword: "video"),
-            ])));
+            }));
       final queryEmailInvocation = jmapRequestBuilder
           .invocation(queryEmailMethod, methodCallId: MethodCallId('c2'));
 
diff --git a/test/jmap/email/search/use_case_test/search_by_after_use_case_test.dart b/test/jmap/email/search/use_case_test/search_by_after_use_case_test.dart
index 9b54f8b..440b6ed 100644
--- a/test/jmap/email/search/use_case_test/search_by_after_use_case_test.dart
+++ b/test/jmap/email/search/use_case_test/search_by_after_use_case_test.dart
@@ -179,7 +179,7 @@ void main() {
     );
 
     if (resultList != null) {
-      resultList..sortEmails(comparator);
+      resultList.sortEmails(comparator);
     }
 
     return resultList?.list;
diff --git a/test/jmap/email/search/use_case_test/search_by_form_use_case_test.dart b/test/jmap/email/search/use_case_test/search_by_form_use_case_test.dart
index 0d3b3e7..55de4ec 100644
--- a/test/jmap/email/search/use_case_test/search_by_form_use_case_test.dart
+++ b/test/jmap/email/search/use_case_test/search_by_form_use_case_test.dart
@@ -174,7 +174,7 @@ void main() {
     );
 
     if (resultList != null) {
-      resultList..sortEmails(comparator);
+      resultList.sortEmails(comparator);
     }
 
     return resultList?.list;
diff --git a/test/jmap/email/search/use_case_test/search_by_time_and_text_use_case_test.dart b/test/jmap/email/search/use_case_test/search_by_time_and_text_use_case_test.dart
index a20b0bb..45dbea4 100644
--- a/test/jmap/email/search/use_case_test/search_by_time_and_text_use_case_test.dart
+++ b/test/jmap/email/search/use_case_test/search_by_time_and_text_use_case_test.dart
@@ -185,7 +185,7 @@ void main() {
     );
 
     if (resultList != null) {
-      resultList..sortEmails(comparator);
+      resultList.sortEmails(comparator);
     }
 
     return resultList?.list;
diff --git a/test/jmap/email/search/use_case_test/search_emails_inbox_use_case_test.dart b/test/jmap/email/search/use_case_test/search_emails_inbox_use_case_test.dart
index 3029e85..fa91863 100644
--- a/test/jmap/email/search/use_case_test/search_emails_inbox_use_case_test.dart
+++ b/test/jmap/email/search/use_case_test/search_emails_inbox_use_case_test.dart
@@ -247,7 +247,7 @@ void main() {
     );
 
     if (resultList != null) {
-      resultList..sortEmails(comparator);
+      resultList.sortEmails(comparator);
     }
 
     return resultList?.list;
diff --git a/test/jmap/email/set/set_email_method_test.dart b/test/jmap/email/set/set_email_method_test.dart
index 336c3ba..128ce3d 100644
--- a/test/jmap/email/set/set_email_method_test.dart
+++ b/test/jmap/email/set/set_email_method_test.dart
@@ -124,7 +124,7 @@ void main() {
             subject: 'set email 3',
             htmlBody: {EmailBodyPart(partId: PartId('a49d'), type: MediaType.parse('text/html'))},
             bodyValues: {
-              PartId('a49d'): EmailBodyValue('test html html', false, false)
+              PartId('a49d'): EmailBodyValue(value: 'test html html', isEncodingProblem: false, isTruncated: false)
             },
           )
         );
@@ -242,7 +242,7 @@ void main() {
               subject: 'set email 3',
               htmlBody: {EmailBodyPart(partId: PartId('a49d'), type: MediaType.parse('text/html'))},
               bodyValues: {
-                PartId('a49d'): EmailBodyValue('test html html', false, false)
+                PartId('a49d'): EmailBodyValue(value: 'test html html', isEncodingProblem: false, isTruncated: false)
               },
               headerUserAgent: {IndividualHeaderIdentifier.headerUserAgent : 'Android/1.0.0 TeamMail/1.0'}
             )
@@ -350,7 +350,7 @@ void main() {
               subject: '[POSTMAN] SEND EMAIL WITH MDN MDN MDN',
               htmlBody: {EmailBodyPart(partId: PartId('abc123'), type: MediaType.parse('text/html'))},
               bodyValues: {
-                PartId('abc123'): EmailBodyValue('[POSTMAN] SEND EMAIL WITH MDN', false, false)
+                PartId('abc123'): EmailBodyValue(value: '[POSTMAN] SEND EMAIL WITH MDN', isEncodingProblem: false, isTruncated: false)
               },
               headerMdn: {IndividualHeaderIdentifier.headerMdn : "qkdo@linagora.com"}
             )
diff --git a/test/jmap/email/sort_list_email_test.dart b/test/jmap/email/sort_list_email_test.dart
index acb1185..cb61af3 100644
--- a/test/jmap/email/sort_list_email_test.dart
+++ b/test/jmap/email/sort_list_email_test.dart
@@ -268,7 +268,7 @@ void main() {
         getEmailInvocation.methodCallId, GetEmailResponse.deserialize);
 
     if (resultList != null) {
-      resultList..sortEmails(comparator);
+      resultList.sortEmails(comparator);
     }
 
     return resultList?.list;
diff --git a/test/jmap/email/submission/set_email_submission_method_test.dart b/test/jmap/email/submission/set_email_submission_method_test.dart
index e95efa1..30b6b2a 100644
--- a/test/jmap/email/submission/set_email_submission_method_test.dart
+++ b/test/jmap/email/submission/set_email_submission_method_test.dart
@@ -172,7 +172,7 @@ void main() {
               to: {EmailAddress("userD", 'userd@qa.open-paas.org')},
               htmlBody: {EmailBodyPart(partId: PartId('mmm'), blobId: Id('aaaa'), type: MediaType.parse('text/html'))},
               bodyValues: {
-                PartId('mmm'): EmailBodyValue('<!DOCTYPE html> <html> <body> <p><b>Hello test send 2</b></p><br><br></body> </html>', false, false)
+                PartId('mmm'): EmailBodyValue(value: '<!DOCTYPE html> <html> <body> <p><b>Hello test send 2</b></p><br><br></body> </html>', isEncodingProblem: false, isTruncated: false)
               }
             )
         );
@@ -188,7 +188,7 @@ void main() {
         ..addOnSuccessUpdateEmail({
           EmailSubmissionId(ReferenceId(ReferencePrefix.defaultPrefix, Id('a1234'))): PatchObject({
             PatchObject.mailboxIdsProperty: {
-              MailboxIdConverter().toJson(MailboxId(Id('5dfb3290-0a14-11ec-b57c-2fef1ee78d9e'))): true
+              const MailboxIdConverter().toJson(MailboxId(Id('5dfb3290-0a14-11ec-b57c-2fef1ee78d9e'))): true
             }
           })
         });
@@ -361,7 +361,7 @@ void main() {
                 to: {EmailAddress("userD", 'userd@qa.open-paas.org')},
                 htmlBody: {EmailBodyPart(partId: PartId('mmm'), blobId: Id('aaaa'), type: MediaType.parse('text/html'))},
                 bodyValues: {
-                  PartId('mmm'): EmailBodyValue('<!DOCTYPE html> <html> <body> <p><b>Hello test send 2</b></p><br><br></body> </html>', false, false)
+                  PartId('mmm'): EmailBodyValue(value: '<!DOCTYPE html> <html> <body> <p><b>Hello test send 2</b></p><br><br></body> </html>', isEncodingProblem: false, isTruncated: false)
                 },
                 headerUserAgent: {IndividualHeaderIdentifier.headerUserAgent : 'Android/1.0.0 TeamMail/1.0'}
             )
@@ -378,7 +378,7 @@ void main() {
         ..addOnSuccessUpdateEmail({
           EmailSubmissionId(ReferenceId(ReferencePrefix.defaultPrefix, Id('a1234'))): PatchObject({
             PatchObject.mailboxIdsProperty: {
-              MailboxIdConverter().toJson(MailboxId(Id('5dfb3290-0a14-11ec-b57c-2fef1ee78d9e'))): true
+              const MailboxIdConverter().toJson(MailboxId(Id('5dfb3290-0a14-11ec-b57c-2fef1ee78d9e'))): true
             }
           })
         });