diff --git a/core.cpp b/core.cpp
index 0fcd09fc6..8f4d64551 100644
--- a/core.cpp
+++ b/core.cpp
@@ -137,12 +137,12 @@ void Core::onFriendRequest(Tox*/* tox*/, const uint8_t* cUserId, const uint8_t*
     emit static_cast<Core*>(core)->friendRequestReceived(CUserId::toString(cUserId), CString::toString(cMessage, cMessageSize));
 }
 
-void Core::onFriendMessage(Tox*/* tox*/, int friendId, uint8_t* cMessage, uint16_t cMessageSize, void* core)
+void Core::onFriendMessage(Tox*/* tox*/, int friendId, const uint8_t* cMessage, uint16_t cMessageSize, void* core)
 {
     emit static_cast<Core*>(core)->friendMessageReceived(friendId, CString::toString(cMessage, cMessageSize));
 }
 
-void Core::onFriendNameChange(Tox*/* tox*/, int friendId, uint8_t* cName, uint16_t cNameSize, void* core)
+void Core::onFriendNameChange(Tox*/* tox*/, int friendId, const uint8_t* cName, uint16_t cNameSize, void* core)
 {
     emit static_cast<Core*>(core)->friendUsernameChanged(friendId, CString::toString(cName, cNameSize));
 }
@@ -152,7 +152,7 @@ void Core::onFriendTypingChange(Tox*/* tox*/, int friendId, uint8_t isTyping, vo
     emit static_cast<Core*>(core)->friendTypingChanged(friendId, isTyping ? true : false);
 }
 
-void Core::onStatusMessageChanged(Tox*/* tox*/, int friendId, uint8_t* cMessage, uint16_t cMessageSize, void* core)
+void Core::onStatusMessageChanged(Tox*/* tox*/, int friendId, const uint8_t* cMessage, uint16_t cMessageSize, void* core)
 {
     emit static_cast<Core*>(core)->friendStatusMessageChanged(friendId, CString::toString(cMessage, cMessageSize));
 }
@@ -186,18 +186,18 @@ void Core::onConnectionStatusChanged(Tox*/* tox*/, int friendId, uint8_t status,
     }
 }
 
-void Core::onAction(Tox*/* tox*/, int friendId, uint8_t *cMessage, uint16_t cMessageSize, void *core)
+void Core::onAction(Tox*/* tox*/, int friendId, const uint8_t *cMessage, uint16_t cMessageSize, void *core)
 {
     emit static_cast<Core*>(core)->actionReceived(friendId, CString::toString(cMessage, cMessageSize));
 }
 
-void Core::onGroupInvite(Tox*, int friendnumber, uint8_t *group_public_key, void *core)
+void Core::onGroupInvite(Tox*, int friendnumber, const uint8_t *group_public_key, void *core)
 {
     qDebug() << QString("Core: Group invite by %1").arg(friendnumber);
     emit static_cast<Core*>(core)->groupInviteReceived(friendnumber, group_public_key);
 }
 
-void Core::onGroupMessage(Tox*, int groupnumber, int friendgroupnumber, uint8_t * message, uint16_t length, void *core)
+void Core::onGroupMessage(Tox*, int groupnumber, int friendgroupnumber, const uint8_t * message, uint16_t length, void *core)
 {
     emit static_cast<Core*>(core)->groupMessageReceived(groupnumber, friendgroupnumber, CString::toString(message, length));
 }
@@ -209,7 +209,7 @@ void Core::onGroupNamelistChange(Tox*, int groupnumber, int peernumber, uint8_t
 }
 
 void Core::onFileSendRequestCallback(Tox*, int32_t friendnumber, uint8_t filenumber, uint64_t filesize,
-                                          uint8_t *filename, uint16_t filename_length, void *core)
+                                          const uint8_t *filename, uint16_t filename_length, void *core)
 {
     qDebug() << QString("Core: Received file request %1 with friend %2").arg(filenumber).arg(friendnumber);
 
@@ -218,7 +218,7 @@ void Core::onFileSendRequestCallback(Tox*, int32_t friendnumber, uint8_t filenum
     emit static_cast<Core*>(core)->fileReceiveRequested(fileRecvQueue.last());
 }
 void Core::onFileControlCallback(Tox*, int32_t friendnumber, uint8_t receive_send, uint8_t filenumber,
-                                      uint8_t control_type, uint8_t*, uint16_t, void *core)
+                                      uint8_t control_type, const uint8_t*, uint16_t, void *core)
 {
     ToxFile* file{nullptr};
     if (receive_send == 1)
@@ -287,7 +287,7 @@ void Core::onFileControlCallback(Tox*, int32_t friendnumber, uint8_t receive_sen
     }
 }
 
-void Core::onFileDataCallback(Tox*, int32_t friendnumber, uint8_t filenumber, uint8_t *data, uint16_t length, void *core)
+void Core::onFileDataCallback(Tox*, int32_t friendnumber, uint8_t filenumber, const uint8_t *data, uint16_t length, void *core)
 {
     ToxFile* file{nullptr};
     for (ToxFile& f : fileRecvQueue)
@@ -793,7 +793,7 @@ QList<QString> Core::getGroupPeerNames(int groupId) const
     return names;
 }
 
-int Core::joinGroupchat(int32_t friendnumber, uint8_t* friend_group_public_key) const
+int Core::joinGroupchat(int32_t friendnumber, const uint8_t* friend_group_public_key) const
 {
     qDebug() << QString("Trying to join groupchat invite by friend %1").arg(friendnumber);
     return tox_join_groupchat(tox, friendnumber, friend_group_public_key);
diff --git a/core.h b/core.h
index 988787a48..fa3e5ec0c 100644
--- a/core.h
+++ b/core.h
@@ -115,7 +115,7 @@ public:
     int getGroupNumberPeers(int groupId) const;
     QString getGroupPeerName(int groupId, int peerId) const;
     QList<QString> getGroupPeerNames(int groupId) const;
-    int joinGroupchat(int32_t friendnumber, uint8_t* friend_group_public_key) const;
+    int joinGroupchat(int32_t friendnumber, const uint8_t* friend_group_public_key) const;
     void quitGroupChat(int groupId) const;
     void dispatchVideoFrame(vpx_image img) const;
 
@@ -178,7 +178,7 @@ signals:
     void friendLastSeenChanged(int friendId, const QDateTime& dateTime);
 
     void emptyGroupCreated(int groupnumber);
-    void groupInviteReceived(int friendnumber, uint8_t *group_public_key);
+    void groupInviteReceived(int friendnumber, const uint8_t *group_public_key);
     void groupMessageReceived(int groupnumber, int friendgroupnumber, const QString& message);
     void groupNamelistChanged(int groupnumber, int peernumber, uint8_t change);
 
@@ -222,21 +222,21 @@ signals:
 
 private:
     static void onFriendRequest(Tox* tox, const uint8_t* cUserId, const uint8_t* cMessage, uint16_t cMessageSize, void* core);
-    static void onFriendMessage(Tox* tox, int friendId, uint8_t* cMessage, uint16_t cMessageSize, void* core);
-    static void onFriendNameChange(Tox* tox, int friendId, uint8_t* cName, uint16_t cNameSize, void* core);
+    static void onFriendMessage(Tox* tox, int friendId, const uint8_t* cMessage, uint16_t cMessageSize, void* core);
+    static void onFriendNameChange(Tox* tox, int friendId, const uint8_t* cName, uint16_t cNameSize, void* core);
     static void onFriendTypingChange(Tox* tox, int friendId, uint8_t isTyping, void* core);
-    static void onStatusMessageChanged(Tox* tox, int friendId, uint8_t* cMessage, uint16_t cMessageSize, void* core);
+    static void onStatusMessageChanged(Tox* tox, int friendId, const uint8_t* cMessage, uint16_t cMessageSize, void* core);
     static void onUserStatusChanged(Tox* tox, int friendId, uint8_t userstatus, void* core);
     static void onConnectionStatusChanged(Tox* tox, int friendId, uint8_t status, void* core);
-    static void onAction(Tox* tox, int friendId, uint8_t* cMessage, uint16_t cMessageSize, void* core);
-    static void onGroupInvite(Tox *tox, int friendnumber, uint8_t *group_public_key, void *userdata);
-    static void onGroupMessage(Tox *tox, int groupnumber, int friendgroupnumber, uint8_t * message, uint16_t length, void *userdata);
+    static void onAction(Tox* tox, int friendId, const uint8_t* cMessage, uint16_t cMessageSize, void* core);
+    static void onGroupInvite(Tox *tox, int friendnumber, const uint8_t *group_public_key, void *userdata);
+    static void onGroupMessage(Tox *tox, int groupnumber, int friendgroupnumber, const uint8_t * message, uint16_t length, void *userdata);
     static void onGroupNamelistChange(Tox *tox, int groupnumber, int peernumber, uint8_t change, void *userdata);
     static void onFileSendRequestCallback(Tox *tox, int32_t friendnumber, uint8_t filenumber, uint64_t filesize,
-                                          uint8_t *filename, uint16_t filename_length, void *userdata);
+                                          const uint8_t *filename, uint16_t filename_length, void *userdata);
     static void onFileControlCallback(Tox *tox, int32_t friendnumber, uint8_t receive_send, uint8_t filenumber,
-                                      uint8_t control_type, uint8_t *data, uint16_t length, void *core);
-    static void onFileDataCallback(Tox *tox, int32_t friendnumber, uint8_t filenumber, uint8_t *data, uint16_t length, void *userdata);
+                                      uint8_t control_type, const uint8_t *data, uint16_t length, void *core);
+    static void onFileDataCallback(Tox *tox, int32_t friendnumber, uint8_t filenumber, const uint8_t *data, uint16_t length, void *userdata);
 
     static void onAvInvite(int32_t call_index, void* toxav);
     static void onAvStart(int32_t call_index, void* toxav);
diff --git a/widget/widget.cpp b/widget/widget.cpp
index cadb62128..fcad53dce 100644
--- a/widget/widget.cpp
+++ b/widget/widget.cpp
@@ -554,7 +554,7 @@ void Widget::copyFriendIdToClipboard(int friendId)
     }
 }
 
-void Widget::onGroupInviteReceived(int32_t friendId, uint8_t* publicKey)
+void Widget::onGroupInviteReceived(int32_t friendId, const uint8_t* publicKey)
 {
     int groupId = core->joinGroupchat(friendId, publicKey);
     if (groupId == -1)
diff --git a/widget/widget.h b/widget/widget.h
index 58997ff1b..edd2d73ba 100644
--- a/widget/widget.h
+++ b/widget/widget.h
@@ -81,7 +81,7 @@ private slots:
     void onFriendMessageReceived(int friendId, const QString& message);
     void onFriendRequestReceived(const QString& userId, const QString& message);
     void onEmptyGroupCreated(int groupId);
-    void onGroupInviteReceived(int32_t friendId, uint8_t *publicKey);
+    void onGroupInviteReceived(int32_t friendId, const uint8_t *publicKey);
     void onGroupMessageReceived(int groupnumber, int friendgroupnumber, const QString& message);
     void onGroupNamelistChanged(int groupnumber, int peernumber, uint8_t change);
     void onGroupWidgetClicked(GroupWidget* widget);