diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9528f501..fc600602 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+# Version 0.5.4
+## Bug fixes
+- Fixed posts duplication
+
+# Version 0.5.3
+## Bug fixes
+- Fixed a bug when creating a poll
+
 # Version 0.5.2
 ## Bug fixes
 - Fixed a bug when creating a post
diff --git a/lib/entities/posts/polls/poll_answer.dart b/lib/entities/posts/polls/poll_answer.dart
index 11a05d4d..3b4f4ff3 100644
--- a/lib/entities/posts/polls/poll_answer.dart
+++ b/lib/entities/posts/polls/poll_answer.dart
@@ -46,4 +46,9 @@ class PollAnswer extends Equatable {
   List<Object> get props {
     return [answer, user.address];
   }
+
+  @override
+  String toString() {
+    return 'PollAnswer { answer: $answer, user: ${user.address} }';
+  }
 }
diff --git a/lib/entities/posts/polls/poll_option.dart b/lib/entities/posts/polls/poll_option.dart
index e98ad73a..19fe307d 100644
--- a/lib/entities/posts/polls/poll_option.dart
+++ b/lib/entities/posts/polls/poll_option.dart
@@ -48,4 +48,9 @@ class PollOption extends Equatable {
   List<Object> get props {
     return [id, text];
   }
+
+  @override
+  String toString() {
+    return 'PollOption { id: $id, text: $text }';
+  }
 }
diff --git a/lib/entities/posts/polls/post_poll.dart b/lib/entities/posts/polls/post_poll.dart
index b919cbbf..74334a5c 100644
--- a/lib/entities/posts/polls/post_poll.dart
+++ b/lib/entities/posts/polls/post_poll.dart
@@ -1,6 +1,3 @@
-import 'dart:convert';
-
-import 'package:crypto/crypto.dart';
 import 'package:equatable/equatable.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:intl/intl.dart';
@@ -88,20 +85,11 @@ class PostPoll extends Equatable {
         options?.isNotEmpty == true;
   }
 
-  /// Returns `true` is the poll is open considering the current time,
-  /// or `false` otherwise.
+  /// Tells if the poll is still open or not based on the current date time.
   bool get isOpen {
     return DateTime.now().isBefore(endDateTime);
   }
 
-  /// Returns the SHA-256 of all the posts contents as a JSON object.
-  /// Some contents are excluded, such as the user answers.
-  String hashContents() {
-    final json = toJson();
-    json.remove('user_answers');
-    return sha256.convert(utf8.encode(jsonEncode(json))).toString();
-  }
-
   /// Returns the JSON representation of this post poll as a [Map].
   Map<String, dynamic> toJson() {
     return _$PostPollToJson(this);
diff --git a/lib/entities/posts/post.dart b/lib/entities/posts/post.dart
index 16ab30ac..c5c70850 100644
--- a/lib/entities/posts/post.dart
+++ b/lib/entities/posts/post.dart
@@ -1,7 +1,4 @@
-import 'dart:convert';
-
 import 'package:collection/collection.dart';
-import 'package:crypto/crypto.dart';
 import 'package:equatable/equatable.dart';
 import 'package:intl/intl.dart';
 import 'package:json_annotation/json_annotation.dart';
@@ -32,8 +29,6 @@ class Post extends Equatable implements Comparable<Post> {
   /// Identifier used to reference the post creation date.
   static const DATE_FIELD = 'created';
 
-  static const LAST_EDITED_FIELD = 'last_edited';
-
   /// Identifier used to reference post ids.
   static const ID_FIELD = 'id';
 
@@ -43,15 +38,7 @@ class Post extends Equatable implements Comparable<Post> {
   /// Identifier used to reference the user field.
   static const OWNER_FIELD = 'user';
 
-  static const LINK_PREVIEW_FIELD = 'link_preview';
-
-  static const REACTIONS_FIELD = 'reactions';
-
-  static const MEDIA_FIELD = 'media';
-
-  static const POLL_FIELD = 'poll';
-
-  static const COMMENTS_FIELD = 'children';
+  static const LOCAL_ID_KEY = 'local_id';
 
   /// Returns the current date and time in UTC time zone, formatted as
   /// it should be to be used as a post creation date or last edit date.
@@ -73,7 +60,7 @@ class Post extends Equatable implements Comparable<Post> {
   @JsonKey(name: DATE_FIELD)
   final String created;
 
-  @JsonKey(name: LAST_EDITED_FIELD)
+  @JsonKey(name: 'last_edited')
   final String lastEdited;
 
   @JsonKey(name: 'allows_comments')
@@ -88,16 +75,16 @@ class Post extends Equatable implements Comparable<Post> {
   @JsonKey(name: 'optional_data', defaultValue: {})
   final Map<String, String> optionalData;
 
-  @JsonKey(name: MEDIA_FIELD, defaultValue: [])
+  @JsonKey(name: 'media', defaultValue: [])
   final List<PostMedia> medias;
 
-  @JsonKey(name: POLL_FIELD, nullable: true)
+  @JsonKey(name: 'poll', nullable: true)
   final PostPoll poll;
 
-  @JsonKey(name: REACTIONS_FIELD, defaultValue: [])
+  @JsonKey(name: 'reactions', defaultValue: [])
   final List<Reaction> reactions;
 
-  @JsonKey(name: COMMENTS_FIELD, defaultValue: [])
+  @JsonKey(name: 'children', defaultValue: [])
   final List<String> commentsIds;
 
   /// Tells if the post has been synced with the blockchain or not
@@ -106,9 +93,7 @@ class Post extends Equatable implements Comparable<Post> {
 
   /// Static method used to implement a custom deserialization of posts.
   static PostStatus _postStatusFromJson(Map<String, dynamic> json) {
-    return json == null
-        ? PostStatus(value: PostStatusValue.TX_SUCCESSFULL)
-        : PostStatus.fromJson(json);
+    return json == null ? PostStatus.txSuccessful() : PostStatus.fromJson(json);
   }
 
   /// Tells whether or not the post has been hidden from the user.
@@ -116,13 +101,13 @@ class Post extends Equatable implements Comparable<Post> {
   final bool hidden;
 
   /// Represents the link preview associated to this post
-  @JsonKey(name: LINK_PREVIEW_FIELD, nullable: true)
+  @JsonKey(name: 'link_preview', nullable: true)
   final RichLinkPreview linkPreview;
 
   Post({
     @required this.id,
     this.parentId = '',
-    this.message,
+    @required this.message,
     @required this.created,
     this.lastEdited,
     this.allowsComments = false,
@@ -178,31 +163,6 @@ class Post extends Equatable implements Comparable<Post> {
         [];
   }
 
-  /// Returns the SHA-256 of all the posts contents as a JSON object.
-  /// Some contents are excluded. Such as:
-  /// - the date
-  /// - the id
-  /// - the status
-  /// - the link preview
-  /// - the reactions
-  /// - the comments
-  String hashContents() {
-    final json = toJson();
-    json.remove(DATE_FIELD);
-    json.remove(LAST_EDITED_FIELD);
-    json.remove(ID_FIELD);
-    json.remove(STATUS_FIELD);
-    json.remove(LINK_PREVIEW_FIELD);
-    json.remove(REACTIONS_FIELD);
-    json.remove(COMMENTS_FIELD);
-    json.remove(MEDIA_FIELD);
-
-    json.remove(POLL_FIELD);
-    json['poll_data'] = poll?.hashContents();
-
-    return sha256.convert(utf8.encode(jsonEncode(json))).toString();
-  }
-
   /// Returns a new [Post] having the same data as `this` one, but
   /// with the specified data replaced.
   Post copyWith({
diff --git a/lib/entities/posts/post_status.dart b/lib/entities/posts/post_status.dart
index c29b020e..16e4d5d3 100644
--- a/lib/entities/posts/post_status.dart
+++ b/lib/entities/posts/post_status.dart
@@ -19,11 +19,27 @@ class PostStatus extends Equatable {
     this.data,
   }) : assert(value != null);
 
+  /// Builds a [PostStatus] having as value [PostStatusValue.STORED_LOCALLY]
+  /// and as data the given [address].
   factory PostStatus.storedLocally(String address) {
-    return PostStatus(
-      value: PostStatusValue.STORED_LOCALLY,
-      data: address,
-    );
+    return PostStatus(value: PostStatusValue.STORED_LOCALLY, data: address);
+  }
+
+  /// Builds a new [PostStatus] with value [PostStatusValue.SENDING_TX].
+  factory PostStatus.sendingTx() {
+    return PostStatus(value: PostStatusValue.SENDING_TX);
+  }
+
+  factory PostStatus.txSent(String txHash) {
+    return PostStatus(value: PostStatusValue.TX_SENT, data: txHash);
+  }
+
+  factory PostStatus.txSuccessful({String txHash}) {
+    return PostStatus(value: PostStatusValue.TX_SUCCESSFULL, data: txHash);
+  }
+
+  factory PostStatus.errored(String error) {
+    return PostStatus(value: PostStatusValue.ERRORED, data: error);
   }
 
   /// Returns true if the status contains an error message.
diff --git a/lib/main.dart b/lib/main.dart
index 7a7279d4..52e9a2c3 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -80,9 +80,9 @@ Future _setupDependencyInjection() async {
     ),
     postsDatabase: await factory.openDatabase(
       'posts.db',
-      version: 4,
+      version: 6,
       onVersionChanged: (db, oldVersion, newVersion) async {
-        if (oldVersion < 4) {
+        if (oldVersion < 6) {
           await deletePosts(db);
         }
       },
diff --git a/lib/repositories/posts/posts_repository_impl.dart b/lib/repositories/posts/posts_repository_impl.dart
index e4f97c59..b06cbb99 100644
--- a/lib/repositories/posts/posts_repository_impl.dart
+++ b/lib/repositories/posts/posts_repository_impl.dart
@@ -110,16 +110,10 @@ class PostsRepositoryImpl extends PostsRepository {
     PostStatus postStatus;
     switch (result.success) {
       case true:
-        postStatus = PostStatus(
-          value: PostStatusValue.TX_SENT,
-          data: result.hash,
-        );
+        postStatus = PostStatus.txSent(result.hash);
         break;
       case false:
-        postStatus = PostStatus(
-          value: PostStatusValue.ERRORED,
-          data: result.error.errorMessage,
-        );
+        postStatus = PostStatus.errored(result.error.errorMessage);
         break;
     }
 
@@ -136,9 +130,8 @@ class PostsRepositoryImpl extends PostsRepository {
     }
 
     // Set the posts as syncing
-    final syncingStatus = PostStatus(value: PostStatusValue.SENDING_TX);
     final syncingPosts = posts.map((post) {
-      return post.copyWith(status: syncingStatus);
+      return post.copyWith(status: PostStatus.sendingTx());
     }).toList();
     await _localPostsSource.savePosts(syncingPosts);
 
@@ -151,10 +144,12 @@ class PostsRepositoryImpl extends PostsRepository {
 
     // emit event that tx has been successfully added to the chain
     if (status.value == PostStatusValue.TX_SENT) {
-      final currentTxAmount =
-          await _localSettingsSource.get(SettingKeys.TX_AMOUNT) ?? 0;
+      final key = SettingKeys.TX_AMOUNT;
+      final currentTxAmount = await _localSettingsSource.get(key) ?? 0;
       await _localSettingsSource.save(
-          SettingKeys.TX_AMOUNT, currentTxAmount + updatedPosts.length);
+        key,
+        currentTxAmount + updatedPosts.length,
+      );
     }
   }
 
diff --git a/lib/sources/chain/models/msgs/chain_poll_data.dart b/lib/sources/chain/models/msgs/chain_poll_data.dart
index ca72e95b..3aa678d1 100644
--- a/lib/sources/chain/models/msgs/chain_poll_data.dart
+++ b/lib/sources/chain/models/msgs/chain_poll_data.dart
@@ -16,9 +16,6 @@ class ChainPollData {
   @JsonKey(name: 'end_date')
   final String endDate;
 
-  @JsonKey(name: 'is_open')
-  final bool isOpen;
-
   @JsonKey(name: 'allows_multiple_answers')
   final bool allowsMultipleAnswers;
 
@@ -32,13 +29,11 @@ class ChainPollData {
     @required this.question,
     @required this.endDate,
     @required this.options,
-    @required this.isOpen,
     @required this.allowsMultipleAnswers,
     @required this.allowsAnswerEdits,
   })  : assert(question != null),
         assert(endDate != null),
         assert(options != null),
-        assert(isOpen != null),
         assert(allowsMultipleAnswers != null),
         assert(allowsAnswerEdits != null);
 
diff --git a/lib/sources/chain/models/msgs/chain_poll_data.g.dart b/lib/sources/chain/models/msgs/chain_poll_data.g.dart
index 538ac24a..3f9598e6 100644
--- a/lib/sources/chain/models/msgs/chain_poll_data.g.dart
+++ b/lib/sources/chain/models/msgs/chain_poll_data.g.dart
@@ -15,7 +15,6 @@ ChainPollData _$ChainPollDataFromJson(Map<String, dynamic> json) {
             ? null
             : ChainPollOption.fromJson(e as Map<String, dynamic>))
         ?.toList(),
-    isOpen: json['is_open'] as bool,
     allowsMultipleAnswers: json['allows_multiple_answers'] as bool,
     allowsAnswerEdits: json['allows_answer_edits'] as bool,
   );
@@ -25,7 +24,6 @@ Map<String, dynamic> _$ChainPollDataToJson(ChainPollData instance) =>
     <String, dynamic>{
       'question': instance.question,
       'end_date': instance.endDate,
-      'is_open': instance.isOpen,
       'allows_multiple_answers': instance.allowsMultipleAnswers,
       'allows_answer_edits': instance.allowsAnswerEdits,
       'provided_answers': instance.options?.map((e) => e?.toJson())?.toList(),
diff --git a/lib/sources/posts/local/local_posts_source.dart b/lib/sources/posts/local/local_posts_source.dart
index 93735969..e91b768d 100644
--- a/lib/sources/posts/local/local_posts_source.dart
+++ b/lib/sources/posts/local/local_posts_source.dart
@@ -33,7 +33,10 @@ class LocalPostsSourceImpl implements LocalPostsSource {
   /// given [post].
   @visibleForTesting
   String getPostKey(Post post) {
-    return post.hashContents();
+    if (post.optionalData.containsKey(Post.LOCAL_ID_KEY)) {
+      return post.optionalData[Post.LOCAL_ID_KEY];
+    }
+    return post.id;
   }
 
   /// Returns a [Filter] that allows to filter out all the posts that are
diff --git a/lib/sources/posts/remote/converters/posts_msg_converter.dart b/lib/sources/posts/remote/converters/posts_msg_converter.dart
index ed9bdced..9e5228ab 100644
--- a/lib/sources/posts/remote/converters/posts_msg_converter.dart
+++ b/lib/sources/posts/remote/converters/posts_msg_converter.dart
@@ -23,7 +23,6 @@ class PostsMsgConverter {
     return ChainPollData(
       question: poll.question,
       endDate: poll.endDate,
-      isOpen: true,
       allowsMultipleAnswers: poll.allowsMultipleAnswers,
       allowsAnswerEdits: poll.allowsAnswerEdits,
       options: poll.options.map((e) {
diff --git a/lib/ui/blocs/posts_list/posts_list_bloc.dart b/lib/ui/blocs/posts_list/posts_list_bloc.dart
index 9ff38e2a..66969b9d 100644
--- a/lib/ui/blocs/posts_list/posts_list_bloc.dart
+++ b/lib/ui/blocs/posts_list/posts_list_bloc.dart
@@ -442,20 +442,14 @@ class PostsListBloc extends Bloc<PostsListEvent, PostsListState> {
   /// Handles the event that tells the Bloc that a transaction has
   /// been successful.
   void _handleTxSuccessfulEvent(TxSuccessful event) async {
-    final status = PostStatus(
-      value: PostStatusValue.TX_SUCCESSFULL,
-      data: event.txHash,
-    );
+    final status = PostStatus.txSuccessful(txHash: event.txHash);
     await _updatePostsStatusUseCase.update(event.txHash, status);
   }
 
   /// Handles the event that tells the Bloc that a transaction has not
   /// been successful.
   void _handleTxFailedEvent(TxFailed event) async {
-    final status = PostStatus(
-      value: PostStatusValue.ERRORED,
-      data: event.error,
-    );
+    final status = PostStatus.errored(event.error);
     await _updatePostsStatusUseCase.update(event.txHash, status);
   }
 
diff --git a/lib/ui/screens/post_create_screen/blocs/post_input/post_input_bloc.dart b/lib/ui/screens/post_create_screen/blocs/post_input/post_input_bloc.dart
index a94a3e17..50093c11 100644
--- a/lib/ui/screens/post_create_screen/blocs/post_input/post_input_bloc.dart
+++ b/lib/ui/screens/post_create_screen/blocs/post_input/post_input_bloc.dart
@@ -193,7 +193,7 @@ class PostInputBloc extends Bloc<PostInputEvent, PostInputState> {
     final post = await _createPostUseCase.create(
       // If the post has a poll, the entered message should
       // be the poll question instead
-      message: state.hasPoll ? null : state.message,
+      message: state.hasPoll ? '' : state.message,
       allowsComments: state.allowsComments,
       parentId: state.parentPost?.id,
       medias: state.medias,
diff --git a/lib/usecases/posts/usecase_create_post.dart b/lib/usecases/posts/usecase_create_post.dart
index 37364149..bb62d1eb 100644
--- a/lib/usecases/posts/usecase_create_post.dart
+++ b/lib/usecases/posts/usecase_create_post.dart
@@ -33,6 +33,9 @@ class CreatePostUseCase {
       subspace: Constants.SUBSPACE,
       owner: account.toUser(),
       status: PostStatus.storedLocally(account.address),
+      optionalData: {
+        Post.LOCAL_ID_KEY: date,
+      },
     );
   }
 }
diff --git a/pubspec.yaml b/pubspec.yaml
index 1228da62..5c375d34 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: mooncake
 description: A decentralized microblogging application based on Desmos
-version: 0.5.2+05200
+version: 0.5.4+05400
 
 environment:
   sdk: ">=2.9.0 <3.0.0"