diff --git a/src/FTPClient_Generic.hpp b/src/FTPClient_Generic.hpp
index e09538e..42d035a 100644
--- a/src/FTPClient_Generic.hpp
+++ b/src/FTPClient_Generic.hpp
@@ -138,12 +138,12 @@ class FTPClient_Generic
     void CloseConnection();
     bool isConnected();
     void NewFile (const char* fileName);
-    void AppendFile( char* fileName);
+    void AppendFile(const char* fileName);
     void WriteData (unsigned char * data, int dataLength);
     void CloseFile ();
     void GetFTPAnswer (char* result = NULL, int offsetStart = 0);
     void GetLastModifiedTime(const char* fileName, char* result);
-    void RenameFile(char* from, char* to);
+    void RenameFile(const char* from, const char* to);
     void Write(const char * str);
     void InitFile(const char* type);
     void ChangeWorkDir(const char * dir);
diff --git a/src/FTPClient_Generic_Impl.h b/src/FTPClient_Generic_Impl.h
index 8207c19..fd1a013 100644
--- a/src/FTPClient_Generic_Impl.h
+++ b/src/FTPClient_Generic_Impl.h
@@ -279,7 +279,7 @@ void FTPClient_Generic::OpenConnection()
 
 /////////////////////////////////////////////
 
-void FTPClient_Generic::RenameFile(char* from, char* to)
+void FTPClient_Generic::RenameFile(const char* from, const char* to)
 {
   FTP_LOGINFO("Send RNFR");
 
@@ -424,7 +424,7 @@ void FTPClient_Generic::InitFile(const char* type)
 
 /////////////////////////////////////////////
 
-void FTPClient_Generic::AppendFile (char* fileName)
+void FTPClient_Generic::AppendFile (const char* fileName)
 {
   FTP_LOGINFO("Send APPE");