diff --git a/src/include/dongle.cpp b/src/include/dongle.cpp
index 270e19a39..6506b7e75 100755
--- a/src/include/dongle.cpp
+++ b/src/include/dongle.cpp
@@ -22,24 +22,19 @@
 // Current dongle
 ///////////////////////////////////////////////////////////
 
-static TDongle* _dongle = NULL;
+static TDongle* _dongle = nullptr;
 
 TDongle& dongle() 
 { 
-  if (_dongle == NULL)
+  if (_dongle == nullptr)
     _dongle = new TDongle;
   return *_dongle; 
 }
 
 bool destroy_dongle()
 {
-  bool ok = _dongle != NULL;
-  if (ok)
-  {
-    delete _dongle;
-    _dongle = NULL;  
-  }
-  return ok;
+  safe_delete(_dongle); 
+  return true;
 }
 
 ///////////////////////////////////////////////////////////
@@ -137,9 +132,10 @@ bool TDongle::ssa_login(const char* mod)
   _module.reset();          // Disattiva tutti i moduli ...
   _module.set(long(BAAUT)); // ... tranne la base
 
-  const int err = xvt_dongle_sa_login(NULL);
+  const int err = xvt_dongle_sa_login(nullptr);
   _serno = (err >= 0) ? err : 0xFFFF;
-	if (_serno == 0xFFFF && is_power_station())
+	if (//_serno == 0xFFFF && 
+		is_power_station())
 		_serno = 0;
   if (_serno != 0xFFFF)
   {
diff --git a/src/include/utility.cpp b/src/include/utility.cpp
index 3c8842d1f..2e42adc60 100755
--- a/src/include/utility.cpp
+++ b/src/include/utility.cpp
@@ -750,8 +750,7 @@ static bool is_sirio_station(const char* hostname)
 		"NBKPEREGOW10",      // Stefano
 	    "NBKPEREGOW8",       // Stefano
 		"NBCALDERONIW10",	 // Simone 
-
-		NULL
+		nullptr
 	};
   for (int i = 0; ranger[i]; i++)
     if (xvt_str_same(hostname, ranger[i]))
diff --git a/src/xvaga/xvt_ssa.cpp b/src/xvaga/xvt_ssa.cpp
index 4b3931188..198674038 100644
--- a/src/xvaga/xvt_ssa.cpp
+++ b/src/xvaga/xvt_ssa.cpp
@@ -174,16 +174,16 @@ TSSA_Pinger::TSSA_Pinger()
 
 int xvt_dongle_sa_login(const char* module)
 {
-  if (_ssa_timer == NULL)
+  if (_ssa_timer == nullptr)
     _ssa_timer = new TSSA_Pinger;
   return _ssa_timer->Login(module);
 }
 
 int xvt_dongle_sa_crypt(unsigned short* data)
 {
-  if (_ssa_timer == NULL)
+  if (_ssa_timer == nullptr)
     return SSA_UTENTE_NON_LOGGATO;
-  if (data == NULL) 
+  if (data == nullptr) 
     return -EACCES;
 
   data[0] ^= 0xDEAD;