diff --git a/examples/Data_Logging/DataLoggingExample6_NMEA/DataLoggingExample6_NMEA.ino b/examples/Data_Logging/DataLoggingExample6_NMEA/DataLoggingExample6_NMEA.ino
new file mode 100644
index 0000000..fcf00c1
--- /dev/null
+++ b/examples/Data_Logging/DataLoggingExample6_NMEA/DataLoggingExample6_NMEA.ino
@@ -0,0 +1,241 @@
+/*
+  Demonstrate how to log NMEA and UBX data simultaneously
+  By: Paul Clark
+  SparkFun Electronics
+  Date: April 13th, 2021
+  License: MIT. See license file for more information but you can
+  basically do whatever you want with this code.
+
+  This example shows how to configure the u-blox GNSS to send PVT reports automatically
+  and log those and any incoming NMEA messages to SD card in UBX format
+
+  ** Please note: this example will only work on processors like the Artemis which have plenty of RAM available **
+
+  This code is intended to be run on the MicroMod Data Logging Carrier Board using the Artemis Processor
+  but can be adapted by changing the chip select pin and SPI definitions:
+  https://www.sparkfun.com/products/16829
+  https://www.sparkfun.com/products/16401
+
+  Hardware Connections:
+  Please see: https://learn.sparkfun.com/tutorials/micromod-data-logging-carrier-board-hookup-guide
+  Insert the Artemis Processor into the MicroMod Data Logging Carrier Board and secure with the screw.
+  Connect your GNSS breakout to the Carrier Board using a Qwiic cable.
+  Connect an antenna to your GNSS board if required.
+  Insert a formatted micro-SD card into the socket on the Carrier Board.
+  Connect the Carrier Board to your computer using a USB-C cable.
+  Ensure you have the SparkFun Apollo3 boards installed: http://boardsmanager/All#SparkFun_Apollo3
+  This code has been tested using version 1.2.1 of the Apollo3 boards on Arduino IDE 1.8.13.
+  Select "SparkFun Artemis MicroMod" as the board type.
+  Press upload to upload the code onto the Artemis.
+  Open the Serial Monitor at 115200 baud to see the output.
+
+  To minimise I2C bus errors, it is a good idea to open the I2C pull-up split pad links on
+  both the MicroMod Data Logging Carrier Board and the u-blox module breakout.
+
+  Feel like supporting open source hardware?
+  Buy a board from SparkFun!
+  ZED-F9P RTK2: https://www.sparkfun.com/products/15136
+  NEO-M8P RTK: https://www.sparkfun.com/products/15005
+  ZOE-M8Q: https://www.sparkfun.com/products/15193
+  SAM-M8Q: https://www.sparkfun.com/products/15210
+*/
+
+#include <SPI.h>
+#include <SD.h>
+#include <Wire.h> //Needed for I2C to GNSS
+
+#include <SparkFun_u-blox_GNSS_Arduino_Library.h> //Click here to get the library: http://librarymanager/All#SparkFun_u-blox_GNSS
+SFE_UBLOX_GNSS myGNSS;
+
+File myFile; //File that all GNSS data is written to
+
+#define sdChipSelect CS //Primary SPI Chip Select is CS for the MicroMod Artemis Processor. Adjust for your processor if necessary.
+
+#define sdWriteSize 512 // Write data to the SD card in blocks of 512 bytes
+#define fileBufferSize 16384 // Allocate 16KBytes of RAM for UBX message storage
+
+unsigned long lastPrint; // Record when the last Serial print took place
+unsigned long bytesWritten = 0; // Record how many bytes have been written to SD card
+
+void setup()
+{
+  Serial.begin(115200);
+  while (!Serial); //Wait for user to open terminal
+  Serial.println("SparkFun u-blox Example");
+
+  pinMode(LED_BUILTIN, OUTPUT); // Flash LED_BUILTIN each time we write to the SD card
+  digitalWrite(LED_BUILTIN, LOW);
+
+  Wire.begin(); // Start I2C communication
+
+#if defined(AM_PART_APOLLO3)
+  Wire.setPullups(0); // On the Artemis, we can disable the internal I2C pull-ups too to help reduce bus errors
+#endif
+
+  while (Serial.available()) // Make sure the Serial buffer is empty
+  {
+    Serial.read();
+  }
+
+  Serial.println(F("Press any key to start logging."));
+
+  while (!Serial.available()) // Wait for the user to press a key
+  {
+    ; // Do nothing
+  }
+
+  delay(100); // Wait, just in case multiple characters were sent
+  
+  while (Serial.available()) // Empty the Serial buffer
+  {
+    Serial.read();
+  }
+
+  Serial.println("Initializing SD card...");
+
+  // See if the card is present and can be initialized:
+  if (!SD.begin(sdChipSelect))
+  {
+    Serial.println("Card failed, or not present. Freezing...");
+    // don't do anything more:
+    while (1);
+  }
+  Serial.println("SD card initialized.");
+
+  // Create or open a file called "PVT_NMEA.ubx" on the SD card.
+  // If the file already exists, the new data is appended to the end of the file.
+  myFile = SD.open("PVT_NMEA.ubx", FILE_WRITE);
+  if(!myFile)
+  {
+    Serial.println(F("Failed to create UBX data file! Freezing..."));
+    while (1);
+  }
+
+  //myGNSS.enableDebugging(); // Uncomment this line to enable lots of helpful GNSS debug messages on Serial
+  //myGNSS.enableDebugging(Serial, true); // Or, uncomment this line to enable only the important GNSS debug messages on Serial
+
+  //myGNSS.disableUBX7Fcheck(); // RAWX data can legitimately contain 0x7F. Uncomment this line to disable the "7F" check in checkUbloxI2C
+
+  // SD cards can occasionally 'hiccup' and a write takes much longer than usual. The buffer needs to be big enough
+  // to hold the backlog of data if/when this happens.
+  // getMaxFileBufferAvail will tell us the maximum number of bytes which the file buffer has contained.
+  myGNSS.setFileBufferSize(fileBufferSize); // setFileBufferSize must be called _before_ .begin
+
+  if (myGNSS.begin() == false) //Connect to the u-blox module using Wire port
+  {
+    Serial.println(F("u-blox GNSS not detected at default I2C address. Please check wiring. Freezing..."));
+    while (1);
+  }
+
+  // Uncomment the next line if you want to reset your module back to the default settings with 1Hz navigation rate
+  // This will (re)enable the standard NMEA messages too
+  // This will also disable any "auto" UBX messages that were enabled and saved by other examples and reduce the load on the I2C bus
+  //myGNSS.factoryDefault(); delay(5000);
+
+  myGNSS.setI2COutput(COM_TYPE_UBX | COM_TYPE_NMEA); //Set the I2C port to output both UBX and NMEA messages
+
+  //myGNSS.saveConfigSelective(VAL_CFG_SUBSEC_IOPORT); //Optional: save (only) the communications port settings to flash and BBR
+
+  myGNSS.setNavigationFrequency(1); //Produce one navigation solution per second
+
+  myGNSS.setAutoPVT(true, false); // Enable automatic NAV PVT messages: without callback; without implicit update
+  myGNSS.logNAVPVT(); // Enable NAV PVT data logging
+
+  myGNSS.enableNMEAMessage(UBX_NMEA_GGA, COM_PORT_I2C, 1); // Ensure the GxGGA (Global positioning system fix data) message is enabled. Send every measurement.
+  myGNSS.enableNMEAMessage(UBX_NMEA_GSA, COM_PORT_I2C, 1); // Ensure the GxGSA (GNSS DOP and Active satellites) message is enabled. Send every measurement.
+  myGNSS.enableNMEAMessage(UBX_NMEA_GSV, COM_PORT_I2C, 1); // Ensure the GxGSV (GNSS satellites in view) message is enabled. Send every measurement.
+
+  myGNSS.setNMEALoggingMask(SFE_UBLOX_FILTER_NMEA_ALL); // Enable logging of all enabled NMEA messages
+  //myGNSS.setNMEALoggingMask(SFE_UBLOX_FILTER_NMEA_GGA | SFE_UBLOX_FILTER_NMEA_GSA); // Or we can, for example, log only GxGGA & GxGSA and ignore GxGSV
+
+  Serial.println(F("Press any key to stop logging."));
+
+  lastPrint = millis(); // Initialize lastPrint
+}
+
+void loop()
+{
+  // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+  myGNSS.checkUblox(); // Check for the arrival of new data and process it.
+
+  // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+  while (myGNSS.fileBufferAvailable() >= sdWriteSize) // Check to see if we have at least sdWriteSize waiting in the buffer
+  {
+    digitalWrite(LED_BUILTIN, HIGH); // Flash LED_BUILTIN each time we write to the SD card
+  
+    uint8_t myBuffer[sdWriteSize]; // Create our own buffer to hold the data while we write it to SD card
+
+    myGNSS.extractFileBufferData((uint8_t *)&myBuffer, sdWriteSize); // Extract exactly sdWriteSize bytes from the UBX file buffer and put them into myBuffer
+
+    myFile.write(myBuffer, sdWriteSize); // Write exactly sdWriteSize bytes from myBuffer to the ubxDataFile on the SD card
+
+    bytesWritten += sdWriteSize; // Update bytesWritten
+
+    // In case the SD writing is slow or there is a lot of data to write, keep checking for the arrival of new data
+    myGNSS.checkUblox(); // Check for the arrival of new data and process it.
+
+    digitalWrite(LED_BUILTIN, LOW); // Turn LED_BUILTIN off again
+  }
+
+  // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+  if (millis() > (lastPrint + 1000)) // Print bytesWritten once per second
+  {
+    Serial.print(F("The number of bytes written to SD card is ")); // Print how many bytes have been written to SD card
+    Serial.println(bytesWritten);
+
+    uint16_t maxBufferBytes = myGNSS.getMaxFileBufferAvail(); // Get how full the file buffer has been (not how full it is now)
+    
+    //Serial.print(F("The maximum number of bytes which the file buffer has contained is: ")); // It is a fun thing to watch how full the buffer gets
+    //Serial.println(maxBufferBytes);
+
+    if (maxBufferBytes > ((fileBufferSize / 5) * 4)) // Warn the user if fileBufferSize was more than 80% full
+    {
+      Serial.println(F("Warning: the file buffer has been over 80% full. Some data may have been lost."));
+    }
+    
+    lastPrint = millis(); // Update lastPrint
+  }
+
+  // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+  if (Serial.available()) // Check if the user wants to stop logging
+  {
+    uint16_t remainingBytes = myGNSS.fileBufferAvailable(); // Check if there are any bytes remaining in the file buffer
+    
+    while (remainingBytes > 0) // While there is still data in the file buffer
+    {
+      digitalWrite(LED_BUILTIN, HIGH); // Flash LED_BUILTIN while we write to the SD card
+      
+      uint8_t myBuffer[sdWriteSize]; // Create our own buffer to hold the data while we write it to SD card
+
+      uint16_t bytesToWrite = remainingBytes; // Write the remaining bytes to SD card sdWriteSize bytes at a time
+      if (bytesToWrite > sdWriteSize)
+      {
+        bytesToWrite = sdWriteSize;
+      }
+  
+      myGNSS.extractFileBufferData((uint8_t *)&myBuffer, bytesToWrite); // Extract bytesToWrite bytes from the UBX file buffer and put them into myBuffer
+
+      myFile.write(myBuffer, bytesToWrite); // Write bytesToWrite bytes from myBuffer to the ubxDataFile on the SD card
+
+      bytesWritten += bytesToWrite; // Update bytesWritten
+
+      remainingBytes -= bytesToWrite; // Decrement remainingBytes
+    }
+
+    digitalWrite(LED_BUILTIN, LOW); // Turn LED_BUILTIN off
+
+    Serial.print(F("The total number of bytes written to SD card is ")); // Print how many bytes have been written to SD card
+    Serial.println(bytesWritten);
+
+    myFile.close(); // Close the data file
+    
+    Serial.println(F("Logging stopped. Freezing..."));
+    while(1); // Do nothing more
+  }
+
+  // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+}
diff --git a/examples/Example25_MeasurementAndNavigationRate/Example25_MeasurementAndNavigationRate.ino b/examples/Example25_MeasurementAndNavigationRate/Example25_MeasurementAndNavigationRate.ino
index c16f6ed..a67fc4e 100644
--- a/examples/Example25_MeasurementAndNavigationRate/Example25_MeasurementAndNavigationRate.ino
+++ b/examples/Example25_MeasurementAndNavigationRate/Example25_MeasurementAndNavigationRate.ino
@@ -81,9 +81,6 @@ void setup()
     while (1);
   }
 
-  // Another trick we can use is to mark the CFG RATE data as stale so we can be sure we read fresh data
-  myGNSS.packetUBXCFGRATE->moduleQueried.moduleQueried.all = 0; // Mark all of the CFG RATE data as stale
-
   // Read and print the updated measurement rate and navigation rate
 
   rate = myGNSS.getMeasurementRate(); //Get the measurement rate of this module
diff --git a/examples/Example28_GetLeapSecondInfo/Example28_GetLeapSecondInfo.ino b/examples/Example28_GetLeapSecondInfo/Example28_GetLeapSecondInfo.ino
new file mode 100644
index 0000000..a96f27c
--- /dev/null
+++ b/examples/Example28_GetLeapSecondInfo/Example28_GetLeapSecondInfo.ino
@@ -0,0 +1,143 @@
+/*
+  Getting leap second event info as SNTP Leap Indicator, time to a leap second event and the number of leap seconds since GPS epoch
+  By: UT2UH
+  Date: April 14th, 2021
+  License: MIT. See license file for more information but you can
+  basically do whatever you want with this code.
+
+  This example shows how to query a u-blox module for the leap second event info to cast to SNTP Leap Indicator enumeration.
+  We also turn off the NMEA output on the I2C port. This decreases the amount of I2C traffic dramatically.
+
+  Leave NMEA parsing behind. Now you can simply ask the module for the datums you want!
+
+  Feel like supporting open source hardware?
+  Buy a board from SparkFun!
+  ZED-F9P RTK2: https://www.sparkfun.com/products/15136
+  NEO-M8P RTK: https://www.sparkfun.com/products/15005
+  SAM-M8Q: https://www.sparkfun.com/products/15106
+
+  Hardware Connections:
+  Plug a Qwiic cable into the GNSS and a BlackBoard
+  If you don't have a platform with a Qwiic connection use the SparkFun Qwiic Breadboard Jumper (https://www.sparkfun.com/products/14425)
+  Open the serial monitor at 115200 baud to see the output
+*/
+
+#include <Wire.h> //Needed for I2C to GNSS
+
+#include <SparkFun_u-blox_GNSS_Arduino_Library.h> //http://librarymanager/All#SparkFun_u-blox_GNSS
+SFE_UBLOX_GNSS myGNSS;
+
+typedef enum { 
+  LI_NO_WARNING,      //Time leaping not scheduled
+  LI_LAST_MINUTE_61_SEC,  //Last minute has 61 seconds
+  LI_LAST_MINUTE_59_SEC,  //Last minute has 59 seconds
+  LI_ALARM_CONDITION    //The NTP server's clock not synchronized
+} ntp_LI_e;
+
+
+long lastTime = 0; //Simple local timer. Limits amount if I2C traffic to u-blox module.
+  
+void setup()
+{
+  Serial.begin(115200);
+  while (!Serial)
+    ; //Wait for user to open terminal
+  Serial.println("SparkFun u-blox Example");
+
+  Wire.begin();
+  
+  if (myGNSS.begin() == false) //Connect to the u-blox module using Wire port
+  {
+    Serial.println(F("u-blox GNSS not detected at default I2C address. Please check wiring. Freezing."));
+    while (1)
+      ;
+  }
+
+  // Uncomment the next line if you need to completely reset your module
+  //myGNSS.factoryDefault(); delay(5000); // Reset everything and wait while the module restarts
+
+  myGNSS.setI2COutput(COM_TYPE_UBX); //Set the I2C port to output UBX only (turn off NMEA noise)
+  myGNSS.saveConfiguration();        //Optional: Save the current settings to flash and BBR
+
+  Serial.println("Compare Unix Epoch given with reference one from https://www.epochconverter.com/");
+  
+}
+
+void loop()
+{
+  //Query module only every second. Doing it more often will just cause I2C traffic.
+  //The module only responds when a new position is available
+  if (millis() - lastTime > 1000)
+  {
+    lastTime = millis(); //Update the timer
+
+    // getUnixEpoch marks the PVT data as stale so you will get Unix time and PVT time on alternate seconds
+
+    uint32_t us;  //microseconds returned by getUnixEpoch()
+    uint32_t epoch = myGNSS.getUnixEpoch();
+    Serial.print("Unix Epoch rounded: ");
+    Serial.print(epoch, DEC);    
+    epoch = myGNSS.getUnixEpoch(us);
+    Serial.print("  Exact Unix Epoch: ");
+    Serial.print(epoch, DEC);
+    Serial.print("  micros: ");
+    Serial.println(us, DEC);
+    int32_t timeToLeapSecEvent;
+    ntp_LI_e leapIndicator = (ntp_LI_e)myGNSS.getLeapIndicator(timeToLeapSecEvent);
+    Serial.print("NTP LI: ");
+    Serial.print(leapIndicator, DEC);
+    switch (leapIndicator){
+      case LI_NO_WARNING:
+        Serial.print(" - No event scheduled");
+        break;
+      case LI_LAST_MINUTE_61_SEC:
+        Serial.print(" - last minute will end at 23:60");
+        break;
+      case LI_LAST_MINUTE_59_SEC:
+        Serial.print(" - last minute will end at 23:58");
+        break; 
+      case LI_ALARM_CONDITION:
+      default:
+        Serial.print(" - Unknown (clock not synchronized)");
+        break; 
+    }
+    Serial.print(". Time to the next leap second event: ");
+    Serial.println(timeToLeapSecEvent, DEC);
+
+    sfe_ublox_ls_src_e leapSecSource;
+    Serial.print("Leap seconds since GPS Epoch (Jan 6th, 1980): ");
+    Serial.print(myGNSS.getCurrentLeapSeconds(leapSecSource), DEC);
+    switch (leapSecSource){
+      case SFE_UBLOX_LS_SRC_DEFAULT:
+        Serial.print(" - hardcoded");
+        break;
+      case SFE_UBLOX_LS_SRC_GLONASS:
+        Serial.print(" - derived from GPS and GLONASS time difference");
+        break;
+      case SFE_UBLOX_LS_SRC_GPS:
+        Serial.print(" - according to GPS");
+        break; 
+      case SFE_UBLOX_LS_SRC_SBAS:
+        Serial.print(" - according to SBAS");
+        break;
+      case SFE_UBLOX_LS_SRC_BEIDOU:
+        Serial.print(" - according to BeiDou");
+        break;
+      case SFE_UBLOX_LS_SRC_GALILEO:
+        Serial.print(" - according to Galileo");
+        break;
+      case SFE_UBLOX_LS_SRC_AIDED:
+        Serial.print(" - last minute will end at 23:58");
+        break; 
+      case SFE_UBLOX_LS_SRC_CONFIGURED:
+        Serial.print(" - as configured)");
+        break;
+      case SFE_UBLOX_LS_SRC_UNKNOWN:
+      default:
+        Serial.print(" - source unknown");
+        break;
+    }
+    Serial.println();
+  }
+  Serial.println();
+}
\ No newline at end of file
diff --git a/examples/Example2_NMEAParsing/Example2_NMEAParsing.ino b/examples/Example2_NMEAParsing/Example2_NMEAParsing.ino
index 35c2001..48b691b 100644
--- a/examples/Example2_NMEAParsing/Example2_NMEAParsing.ino
+++ b/examples/Example2_NMEAParsing/Example2_NMEAParsing.ino
@@ -45,6 +45,10 @@ void setup()
     Serial.println(F("u-blox GNSS not detected at default I2C address. Please check wiring. Freezing."));
     while (1);
   }
+
+  myGNSS.setProcessNMEAMask(SFE_UBLOX_FILTER_NMEA_ALL); // Make sure the library is passing all NMEA messages to processNMEA
+
+  myGNSS.setProcessNMEAMask(SFE_UBLOX_FILTER_NMEA_GGA); // Or, we can be kind to MicroNMEA and _only_ pass the GGA messages to it
 }
 
 void loop()
@@ -60,12 +64,12 @@ void loop()
     Serial.println(latitude_mdeg / 1000000., 6);
     Serial.print("Longitude (deg): ");
     Serial.println(longitude_mdeg / 1000000., 6);
+
+    nmea.clear(); // Clear the MicroNMEA storage to make sure we are getting fresh data
   }
   else
   {
-    Serial.print("No Fix - ");
-    Serial.print("Num. satellites: ");
-    Serial.println(nmea.getNumSatellites());
+    Serial.println("Waiting for fresh data");
   }
 
   delay(250); //Don't pound too hard on the I2C bus
diff --git a/keywords.txt b/keywords.txt
index f320104..b2b7cab 100644
--- a/keywords.txt
+++ b/keywords.txt
@@ -28,6 +28,7 @@ UBX_NAV_HPPOSECEF_data_t	KEYWORD1
 UBX_NAV_HPPOSLLH_data_t	KEYWORD1
 UBX_NAV_CLOCK_data_t	KEYWORD1
 UBX_NAV_RELPOSNED_data_t	KEYWORD1
+UBX_NAV_TIMELS_data_t	KEYWORD1
 
 UBX_RXM_SFRBX_data_t	KEYWORD1
 UBX_RXM_RAWX_data_t	KEYWORD1
@@ -264,6 +265,11 @@ initPacketUBXNAVCLOCK	KEYWORD2
 flushNAVCLOCK	KEYWORD2
 logNAVCLOCK	KEYWORD2
 
+getLeapSecondEvent	KEYWORD2
+getLeapIndicator    KEYWORD2
+getCurrentLeapSeconds   KEYWORD2
+initPacketUBXNAVTIMELS	KEYWORD2
+
 getSurveyStatus	KEYWORD2
 initPacketUBXNAVSVIN	KEYWORD2
 
@@ -382,12 +388,18 @@ initPacketUBXHNRPVT	KEYWORD2
 flushHNRPVT	KEYWORD2
 logHNRPVT	KEYWORD2
 
+setNMEALoggingMask	KEYWORD2
+getNMEALoggingMask	KEYWORD2
+setProcessNMEAMask	KEYWORD2
+getProcessNMEAMask	KEYWORD2
+
 setNavigationFrequency	KEYWORD2
 getNavigationFrequency	KEYWORD2
 setMeasurementRate	KEYWORD2
 getMeasurementRate	KEYWORD2
 setNavigationRate	KEYWORD2
 getNavigationRate	KEYWORD2
+flushCFGRATE	KEYWORD2
 
 getGeometricDOP	KEYWORD2
 getPositionDOP	KEYWORD2
@@ -543,16 +555,41 @@ UBX_NMEA_GLQ	LITERAL1
 UBX_NMEA_GNQ	LITERAL1
 UBX_NMEA_GNS	LITERAL1
 UBX_NMEA_GPQ	LITERAL1
+UBX_NMEA_GQQ	LITERAL1
 UBX_NMEA_GRS	LITERAL1
 UBX_NMEA_GSA	LITERAL1
 UBX_NMEA_GST	LITERAL1
 UBX_NMEA_GSV	LITERAL1
+UBX_NMEA_RLM	LITERAL1
 UBX_NMEA_RMC	LITERAL1
 UBX_NMEA_TXT	LITERAL1
 UBX_NMEA_VLW	LITERAL1
 UBX_NMEA_VTG	LITERAL1
 UBX_NMEA_ZDA	LITERAL1
 
+SFE_UBLOX_FILTER_NMEA_ALL	LITERAL1
+SFE_UBLOX_FILTER_NMEA_DTM	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GAQ	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GBQ	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GBS	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GGA	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GLL	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GLQ	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GNQ	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GNS	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GPQ	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GQQ	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GRS	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GSA	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GST	LITERAL1
+SFE_UBLOX_FILTER_NMEA_GSV	LITERAL1
+SFE_UBLOX_FILTER_NMEA_RLM	LITERAL1
+SFE_UBLOX_FILTER_NMEA_RMC	LITERAL1
+SFE_UBLOX_FILTER_NMEA_TXT	LITERAL1
+SFE_UBLOX_FILTER_NMEA_VLW	LITERAL1
+SFE_UBLOX_FILTER_NMEA_VTG	LITERAL1
+SFE_UBLOX_FILTER_NMEA_ZDA	LITERAL1
+
 UBX_NAV_ATT	LITERAL1
 UBX_NAV_CLOCK	LITERAL1
 UBX_NAV_DOP	LITERAL1
@@ -566,6 +603,7 @@ UBX_NAV_RELPOSNED	LITERAL1
 UBX_NAV_RESETODO	LITERAL1
 UBX_NAV_STATUS	LITERAL1
 UBX_NAV_SVIN	LITERAL1
+UBX_NAV_TIMELS	LITERAL1
 UBX_NAV_VELECEF	LITERAL1
 UBX_NAV_VELNED	LITERAL1
 
diff --git a/library.properties b/library.properties
index 1e27608..1baf2ae 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=SparkFun u-blox GNSS Arduino Library
-version=2.0.5
+version=2.0.6
 author=SparkFun Electronics <techsupport@sparkfun.com>
 maintainer=SparkFun Electronics <sparkfun.com>
 sentence=Library for I2C and Serial Communication with u-blox GNSS modules<br/><br/>
diff --git a/src/SparkFun_u-blox_GNSS_Arduino_Library.cpp b/src/SparkFun_u-blox_GNSS_Arduino_Library.cpp
index 2f71233..fcd8cfb 100644
--- a/src/SparkFun_u-blox_GNSS_Arduino_Library.cpp
+++ b/src/SparkFun_u-blox_GNSS_Arduino_Library.cpp
@@ -50,6 +50,9 @@ SFE_UBLOX_GNSS::SFE_UBLOX_GNSS(void)
     pinMode((uint8_t)debugPin, OUTPUT);
     digitalWrite((uint8_t)debugPin, HIGH);
   }
+
+  _logNMEA.all = 0; // Default to passing no NMEA messages to the file buffer
+  _processNMEA.all = SFE_UBLOX_FILTER_NMEA_ALL; // Default to passing all NMEA messages to processNMEA
 }
 
 //Stop all automatic message processing. Free all used RAM
@@ -82,6 +85,12 @@ void SFE_UBLOX_GNSS::end(void)
     delete[] currentGeofenceParams;
     currentGeofenceParams = NULL; // Redundant?
   }
+
+  if (packetUBXNAVTIMELS != NULL)
+  {
+    delete[] packetUBXNAVTIMELS;
+    packetUBXNAVTIMELS = NULL; // Redundant?
+  }
   
   if (packetUBXNAVPOSECEF != NULL)
   {
@@ -789,6 +798,9 @@ boolean SFE_UBLOX_GNSS::checkAutomatic(uint8_t Class, uint8_t ID)
         case UBX_NAV_CLOCK:
           if (packetUBXNAVCLOCK != NULL) result = true;
         break;
+        case UBX_NAV_TIMELS:
+          if (packetUBXNAVTIMELS != NULL) result = true;
+        break;
         case UBX_NAV_SVIN:
           if (packetUBXNAVSVIN != NULL) result = true;
         break;
@@ -916,6 +928,9 @@ uint16_t SFE_UBLOX_GNSS::getMaxPayloadSize(uint8_t Class, uint8_t ID)
         case UBX_NAV_CLOCK:
           maxSize = UBX_NAV_CLOCK_LEN;
         break;
+        case UBX_NAV_TIMELS:
+          maxSize = UBX_NAV_TIMELS_LEN;
+        break;
         case UBX_NAV_SVIN:
           maxSize = UBX_NAV_SVIN_LEN;
         break;
@@ -1020,6 +1035,7 @@ void SFE_UBLOX_GNSS::process(uint8_t incoming, ubxPacket *incomingUBX, uint8_t r
     }
     else if (incoming == '$')
     {
+      nmeaByteCounter = 0; // Reset the NMEA byte counter
       currentSentence = NMEA;
     }
     else if (incoming == 0xD3) //RTCM frames start with 0xD3
@@ -1241,9 +1257,58 @@ void SFE_UBLOX_GNSS::process(uint8_t incoming, ubxPacket *incomingUBX, uint8_t r
     //Finally, increment the frame counter
     ubxFrameCounter++;
   }
-  else if (currentSentence == NMEA)
+  else if (currentSentence == NMEA) // Process incoming NMEA mesages. Selectively log if desired.
   {
-    processNMEA(incoming); //Process each NMEA character
+    if ((nmeaByteCounter == 0) && (incoming != '$'))
+    {
+      currentSentence = NONE; //Something went wrong. Reset. (Almost certainly redundant!)
+    }
+    else if ((nmeaByteCounter == 1) && (incoming != 'G'))
+    {
+      currentSentence = NONE; //Something went wrong. Reset.
+    }
+    else if ((nmeaByteCounter >= 0) && (nmeaByteCounter <= 5))
+    {
+      nmeaAddressField[nmeaByteCounter] = incoming; // Store the start character and NMEA address field
+    }
+
+    if (nmeaByteCounter == 5)
+    {
+      // We've just received the end of the address field. Check if it is selected for logging
+      if (logThisNMEA())
+      {
+        storeFileBytes(&nmeaAddressField[0], 6); // Add start character and address field to the file buffer
+      }
+      // Check if it should be passed to processNMEA
+      if (processThisNMEA())
+      {
+        processNMEA(nmeaAddressField[0]); //Process the start character and address field
+        processNMEA(nmeaAddressField[1]);
+        processNMEA(nmeaAddressField[2]);
+        processNMEA(nmeaAddressField[3]);
+        processNMEA(nmeaAddressField[4]);
+        processNMEA(nmeaAddressField[5]);
+      }
+    }
+
+    if ((nmeaByteCounter > 5) || (nmeaByteCounter < 0)) // Should we add incoming to the file buffer and/or pass it to processNMEA?
+    {
+      if (logThisNMEA())
+        storeFileBytes(&incoming, 1); // Add incoming to the file buffer
+      if (processThisNMEA())
+        processNMEA(incoming); // Pass incoming to processNMEA
+    }
+
+    if (incoming == '*')
+      nmeaByteCounter = -5; // We are expecting * plus two checksum bytes plus CR and LF
+
+    nmeaByteCounter++; // Increment the byte counter
+
+    if (nmeaByteCounter == maxNMEAByteCount) // Check if we have processed too many bytes
+      currentSentence = NONE; //Something went wrong. Reset.
+
+    if (nmeaByteCounter == 0) // Check if we are done
+      currentSentence = NONE; // All done!
   }
   else if (currentSentence == RTCM)
   {
@@ -1251,6 +1316,68 @@ void SFE_UBLOX_GNSS::process(uint8_t incoming, ubxPacket *incomingUBX, uint8_t r
   }
 }
 
+// PRIVATE: Return true if we should add this NMEA message to the file buffer for logging
+boolean SFE_UBLOX_GNSS::logThisNMEA()
+{
+  if (_logNMEA.bits.all == 1) return (true);
+  if ((nmeaAddressField[3] == 'D') && (nmeaAddressField[4] == 'T') && (nmeaAddressField[5] == 'M') && (_logNMEA.bits.UBX_NMEA_DTM == 1)) return (true);
+  if (nmeaAddressField[3] == 'G')
+  {
+    if ((nmeaAddressField[4] == 'A') && (nmeaAddressField[5] == 'Q') && (_logNMEA.bits.UBX_NMEA_GAQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'B') && (nmeaAddressField[5] == 'Q') && (_logNMEA.bits.UBX_NMEA_GBQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'B') && (nmeaAddressField[5] == 'S') && (_logNMEA.bits.UBX_NMEA_GBS == 1)) return (true);
+    if ((nmeaAddressField[4] == 'G') && (nmeaAddressField[5] == 'A') && (_logNMEA.bits.UBX_NMEA_GGA == 1)) return (true);
+    if ((nmeaAddressField[4] == 'L') && (nmeaAddressField[5] == 'L') && (_logNMEA.bits.UBX_NMEA_GLL == 1)) return (true);
+    if ((nmeaAddressField[4] == 'L') && (nmeaAddressField[5] == 'Q') && (_logNMEA.bits.UBX_NMEA_GLQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'N') && (nmeaAddressField[5] == 'Q') && (_logNMEA.bits.UBX_NMEA_GNQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'N') && (nmeaAddressField[5] == 'S') && (_logNMEA.bits.UBX_NMEA_GNS == 1)) return (true);
+    if ((nmeaAddressField[4] == 'P') && (nmeaAddressField[5] == 'Q') && (_logNMEA.bits.UBX_NMEA_GPQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'Q') && (nmeaAddressField[5] == 'Q') && (_logNMEA.bits.UBX_NMEA_GQQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'R') && (nmeaAddressField[5] == 'S') && (_logNMEA.bits.UBX_NMEA_GRS == 1)) return (true);
+    if ((nmeaAddressField[4] == 'S') && (nmeaAddressField[5] == 'A') && (_logNMEA.bits.UBX_NMEA_GSA == 1)) return (true);
+    if ((nmeaAddressField[4] == 'S') && (nmeaAddressField[5] == 'T') && (_logNMEA.bits.UBX_NMEA_GST == 1)) return (true);
+    if ((nmeaAddressField[4] == 'S') && (nmeaAddressField[5] == 'V') && (_logNMEA.bits.UBX_NMEA_GSV == 1)) return (true);
+  }
+  if ((nmeaAddressField[3] == 'R') && (nmeaAddressField[4] == 'L') && (nmeaAddressField[5] == 'M') && (_logNMEA.bits.UBX_NMEA_RLM == 1)) return (true);
+  if ((nmeaAddressField[3] == 'R') && (nmeaAddressField[4] == 'M') && (nmeaAddressField[5] == 'C') && (_logNMEA.bits.UBX_NMEA_RMC == 1)) return (true);
+  if ((nmeaAddressField[3] == 'T') && (nmeaAddressField[4] == 'X') && (nmeaAddressField[5] == 'T') && (_logNMEA.bits.UBX_NMEA_TXT == 1)) return (true);
+  if ((nmeaAddressField[3] == 'V') && (nmeaAddressField[4] == 'L') && (nmeaAddressField[5] == 'W') && (_logNMEA.bits.UBX_NMEA_VLW == 1)) return (true);
+  if ((nmeaAddressField[3] == 'V') && (nmeaAddressField[4] == 'T') && (nmeaAddressField[5] == 'G') && (_logNMEA.bits.UBX_NMEA_VTG == 1)) return (true);
+  if ((nmeaAddressField[3] == 'Z') && (nmeaAddressField[4] == 'D') && (nmeaAddressField[5] == 'A') && (_logNMEA.bits.UBX_NMEA_ZDA == 1)) return (true);
+  return (false);
+}
+
+// PRIVATE: Return true if we should pass this NMEA message to processNMEA
+boolean SFE_UBLOX_GNSS::processThisNMEA()
+{
+  if (_processNMEA.bits.all == 1) return (true);
+  if ((nmeaAddressField[3] == 'D') && (nmeaAddressField[4] == 'T') && (nmeaAddressField[5] == 'M') && (_processNMEA.bits.UBX_NMEA_DTM == 1)) return (true);
+  if (nmeaAddressField[3] == 'G')
+  {
+    if ((nmeaAddressField[4] == 'A') && (nmeaAddressField[5] == 'Q') && (_processNMEA.bits.UBX_NMEA_GAQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'B') && (nmeaAddressField[5] == 'Q') && (_processNMEA.bits.UBX_NMEA_GBQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'B') && (nmeaAddressField[5] == 'S') && (_processNMEA.bits.UBX_NMEA_GBS == 1)) return (true);
+    if ((nmeaAddressField[4] == 'G') && (nmeaAddressField[5] == 'A') && (_processNMEA.bits.UBX_NMEA_GGA == 1)) return (true);
+    if ((nmeaAddressField[4] == 'L') && (nmeaAddressField[5] == 'L') && (_processNMEA.bits.UBX_NMEA_GLL == 1)) return (true);
+    if ((nmeaAddressField[4] == 'L') && (nmeaAddressField[5] == 'Q') && (_processNMEA.bits.UBX_NMEA_GLQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'N') && (nmeaAddressField[5] == 'Q') && (_processNMEA.bits.UBX_NMEA_GNQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'N') && (nmeaAddressField[5] == 'S') && (_processNMEA.bits.UBX_NMEA_GNS == 1)) return (true);
+    if ((nmeaAddressField[4] == 'P') && (nmeaAddressField[5] == 'Q') && (_processNMEA.bits.UBX_NMEA_GPQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'Q') && (nmeaAddressField[5] == 'Q') && (_processNMEA.bits.UBX_NMEA_GQQ == 1)) return (true);
+    if ((nmeaAddressField[4] == 'R') && (nmeaAddressField[5] == 'S') && (_processNMEA.bits.UBX_NMEA_GRS == 1)) return (true);
+    if ((nmeaAddressField[4] == 'S') && (nmeaAddressField[5] == 'A') && (_processNMEA.bits.UBX_NMEA_GSA == 1)) return (true);
+    if ((nmeaAddressField[4] == 'S') && (nmeaAddressField[5] == 'T') && (_processNMEA.bits.UBX_NMEA_GST == 1)) return (true);
+    if ((nmeaAddressField[4] == 'S') && (nmeaAddressField[5] == 'V') && (_processNMEA.bits.UBX_NMEA_GSV == 1)) return (true);
+  }
+  if ((nmeaAddressField[3] == 'R') && (nmeaAddressField[4] == 'L') && (nmeaAddressField[5] == 'M') && (_processNMEA.bits.UBX_NMEA_RLM == 1)) return (true);
+  if ((nmeaAddressField[3] == 'R') && (nmeaAddressField[4] == 'M') && (nmeaAddressField[5] == 'C') && (_processNMEA.bits.UBX_NMEA_RMC == 1)) return (true);
+  if ((nmeaAddressField[3] == 'T') && (nmeaAddressField[4] == 'X') && (nmeaAddressField[5] == 'T') && (_processNMEA.bits.UBX_NMEA_TXT == 1)) return (true);
+  if ((nmeaAddressField[3] == 'V') && (nmeaAddressField[4] == 'L') && (nmeaAddressField[5] == 'W') && (_processNMEA.bits.UBX_NMEA_VLW == 1)) return (true);
+  if ((nmeaAddressField[3] == 'V') && (nmeaAddressField[4] == 'T') && (nmeaAddressField[5] == 'G') && (_processNMEA.bits.UBX_NMEA_VTG == 1)) return (true);
+  if ((nmeaAddressField[3] == 'Z') && (nmeaAddressField[4] == 'D') && (nmeaAddressField[5] == 'A') && (_processNMEA.bits.UBX_NMEA_ZDA == 1)) return (true);
+  return (false);
+}
+
 //This is the default or generic NMEA processor. We're only going to pipe the data to serial port so we can see it.
 //User could overwrite this function to pipe characters to nmea.process(c) of tinyGPS or MicroNMEA
 //Or user could pipe each character to a buffer, radio, etc.
@@ -1945,6 +2072,26 @@ void SFE_UBLOX_GNSS::processUBXpacket(ubxPacket *msg)
         }
       }
     }
+    else if (msg->id == UBX_NAV_TIMELS && msg->len == UBX_NAV_TIMELS_LEN)
+    {
+      //Parse various byte fields into storage - but only if we have memory allocated for it
+      if (packetUBXNAVTIMELS != NULL)
+      {
+        packetUBXNAVTIMELS->data.iTOW = extractLong(msg, 0);
+        packetUBXNAVTIMELS->data.version = extractByte(msg, 4);
+        packetUBXNAVTIMELS->data.srcOfCurrLs = extractByte(msg, 8);
+        packetUBXNAVTIMELS->data.currLs = extractSignedChar(msg, 9);
+        packetUBXNAVTIMELS->data.srcOfLsChange = extractByte(msg, 10);
+        packetUBXNAVTIMELS->data.lsChange = extractSignedChar(msg, 11);
+        packetUBXNAVTIMELS->data.timeToLsEvent = extractSignedLong(msg, 12);
+        packetUBXNAVTIMELS->data.dateOfLsGpsWn = extractInt(msg, 16);
+        packetUBXNAVTIMELS->data.dateOfLsGpsDn = extractInt(msg, 18);
+        packetUBXNAVTIMELS->data.valid.all = extractSignedChar(msg, 23);
+
+        //Mark all datums as fresh (not read before)
+        packetUBXNAVTIMELS->moduleQueried.moduleQueried.all = 0xFFFFFFFF;
+      }
+    }
     else if (msg->id == UBX_NAV_SVIN && msg->len == UBX_NAV_SVIN_LEN)
     {
       //Parse various byte fields into storage - but only if we have memory allocated for it
@@ -6858,6 +7005,53 @@ void SFE_UBLOX_GNSS::logNAVCLOCK(boolean enabled)
   packetUBXNAVCLOCK->automaticFlags.flags.bits.addToFileBuffer = (uint8_t)enabled;
 }
 
+// ***** NAV TIMELS automatic support
+
+//Reads leap second event information and sets the global variables
+//for future leap second change and number of leap seconds since GPS epoch
+//Returns true if commands was successful
+boolean SFE_UBLOX_GNSS::getLeapSecondEvent(uint16_t maxWait)
+{
+  if (packetUBXNAVTIMELS == NULL) initPacketUBXNAVTIMELS(); //Check that RAM has been allocated for the TIMELS data
+  if (packetUBXNAVTIMELS == NULL) // Abort if the RAM allocation failed
+    return (false);
+
+  packetCfg.cls = UBX_CLASS_NAV;
+  packetCfg.id = UBX_NAV_TIMELS;
+  packetCfg.len = 0;
+  packetCfg.startingSpot = 0;
+
+  //The data is parsed as part of processing the response
+  sfe_ublox_status_e retVal = sendCommand(&packetCfg, maxWait);
+
+  if (retVal == SFE_UBLOX_STATUS_DATA_RECEIVED)
+    return (true);
+
+  if (retVal == SFE_UBLOX_STATUS_DATA_OVERWRITTEN)
+  {
+    return (true);
+  }
+
+  return (false);
+}
+
+// PRIVATE: Allocate RAM for packetUBXNAVTIMELS and initialize it
+boolean SFE_UBLOX_GNSS::initPacketUBXNAVTIMELS()
+{
+  packetUBXNAVTIMELS = new UBX_NAV_TIMELS_t; //Allocate RAM for the main struct
+  if (packetUBXNAVTIMELS == NULL)
+  {
+    if ((_printDebug == true) || (_printLimitedDebug == true)) // This is important. Print this if doing limited debugging
+      _debugSerial->println(F("initPacketUBXNAVTIMELS: PANIC! RAM allocation failed!"));
+    return (false);
+  }
+  packetUBXNAVTIMELS->automaticFlags.flags.all = 0;
+  packetUBXNAVTIMELS->callbackPointer = NULL;
+  packetUBXNAVTIMELS->callbackData = NULL;
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.all = 0;
+  return (true);
+}
+
 // ***** NAV SVIN automatic support
 
 //Reads survey in status and sets the global variables
@@ -7387,38 +7581,25 @@ boolean SFE_UBLOX_GNSS::getNavigationFrequencyInternal(uint16_t maxWait)
   if (packetUBXCFGRATE == NULL) //Bail if the RAM allocation failed
     return (false);
 
-  if (packetUBXCFGRATE->automaticFlags.flags.bits.automatic && packetUBXCFGRATE->automaticFlags.flags.bits.implicitUpdate)
-  {
-    //The GPS is automatically reporting, we just check whether we got unread data
-    checkUbloxInternal(&packetCfg, UBX_CLASS_CFG, UBX_CFG_RATE);
-    return packetUBXCFGRATE->moduleQueried.moduleQueried.bits.all;
-  }
-  else if (packetUBXCFGRATE->automaticFlags.flags.bits.automatic && !packetUBXCFGRATE->automaticFlags.flags.bits.implicitUpdate)
-  {
-    //Someone else has to call checkUblox for us...
-    return (false);
-  }
-  else
-  {
-    //The GPS is not automatically reporting navigation rate so we have to poll explicitly
-    packetCfg.cls = UBX_CLASS_CFG;
-    packetCfg.id = UBX_CFG_RATE;
-    packetCfg.len = 0;
-    packetCfg.startingSpot = 0;
-
-    //The data is parsed as part of processing the response
-    sfe_ublox_status_e retVal = sendCommand(&packetCfg, maxWait);
+  // The CFG RATE message will never be produced automatically - that would be pointless.
+  // There is no setAutoCFGRATE function. We always need to poll explicitly.
+  packetCfg.cls = UBX_CLASS_CFG;
+  packetCfg.id = UBX_CFG_RATE;
+  packetCfg.len = 0;
+  packetCfg.startingSpot = 0;
 
-    if (retVal == SFE_UBLOX_STATUS_DATA_RECEIVED)
-      return (true);
+  //The data is parsed as part of processing the response
+  sfe_ublox_status_e retVal = sendCommand(&packetCfg, maxWait);
 
-    if (retVal == SFE_UBLOX_STATUS_DATA_OVERWRITTEN)
-    {
-      return (true);
-    }
+  if (retVal == SFE_UBLOX_STATUS_DATA_RECEIVED)
+    return (true);
 
-    return (false);
+  if (retVal == SFE_UBLOX_STATUS_DATA_OVERWRITTEN)
+  {
+    return (true);
   }
+
+  return (false);
 }
 
 // PRIVATE: Allocate RAM for packetUBXCFGRATE and initialize it
@@ -7431,10 +7612,10 @@ boolean SFE_UBLOX_GNSS::initPacketUBXCFGRATE()
       _debugSerial->println(F("initPacketUBXCFGRATE: PANIC! RAM allocation failed!"));
     return (false);
   }
-  packetUBXCFGRATE->automaticFlags.flags.all = 0;
-  packetUBXCFGRATE->callbackPointer = NULL;
-  packetUBXCFGRATE->callbackData = NULL;
-  packetUBXCFGRATE->moduleQueried.moduleQueried.all = 0;
+  packetUBXCFGRATE->automaticFlags.flags.all = 0; // Redundant
+  packetUBXCFGRATE->callbackPointer = NULL; // Redundant
+  packetUBXCFGRATE->callbackData = NULL; // Redundant
+  packetUBXCFGRATE->moduleQueried.moduleQueried.all = 0; // Mark all data as stale/read
   return (true);
 }
 
@@ -9086,6 +9267,29 @@ void SFE_UBLOX_GNSS::logHNRPVT(boolean enabled)
   packetUBXHNRPVT->automaticFlags.flags.bits.addToFileBuffer = (uint8_t)enabled;
 }
 
+// ***** Helper Functions for NMEA Logging / Processing
+
+// Log selected NMEA messages to file buffer - if the messages are enabled and if the file buffer exists
+// User needs to call setFileBufferSize before .begin
+void SFE_UBLOX_GNSS::setNMEALoggingMask(uint32_t messages)
+{
+  _logNMEA.all = messages;
+}
+uint32_t SFE_UBLOX_GNSS::getNMEALoggingMask()
+{
+  return (_logNMEA.all);
+}
+
+// Pass selected NMEA messages to processNMEA
+void SFE_UBLOX_GNSS::setProcessNMEAMask(uint32_t messages)
+{
+  _processNMEA.all = messages;
+}
+uint32_t SFE_UBLOX_GNSS::getProcessNMEAMask()
+{
+  return (_processNMEA.all);
+}
+
 // ***** CFG RATE Helper Functions
 
 //Set the rate at which the module will give us an updated navigation solution
@@ -9114,7 +9318,11 @@ boolean SFE_UBLOX_GNSS::setNavigationFrequency(uint8_t navFreq, uint16_t maxWait
   payloadCfg[0] = measurementRate & 0xFF; //measRate LSB
   payloadCfg[1] = measurementRate >> 8;   //measRate MSB
 
-  return ((sendCommand(&packetCfg, maxWait)) == SFE_UBLOX_STATUS_DATA_SENT); // We are only expecting an ACK
+  boolean result = ((sendCommand(&packetCfg, maxWait)) == SFE_UBLOX_STATUS_DATA_SENT); // We are only expecting an ACK
+
+  flushCFGRATE(); // Mark the polled measurement and navigation rate data as stale
+
+  return (result);
 }
 
 //Get the rate at which the module is outputting nav solutions
@@ -9155,7 +9363,11 @@ boolean SFE_UBLOX_GNSS::setMeasurementRate(uint16_t rate, uint16_t maxWait)
   payloadCfg[0] = rate & 0xFF; //measRate LSB
   payloadCfg[1] = rate >> 8;   //measRate MSB
 
-  return ((sendCommand(&packetCfg, maxWait)) == SFE_UBLOX_STATUS_DATA_SENT); // We are only expecting an ACK
+  boolean result = ((sendCommand(&packetCfg, maxWait)) == SFE_UBLOX_STATUS_DATA_SENT); // We are only expecting an ACK
+
+  flushCFGRATE(); // Mark the polled measurement and navigation rate data as stale
+
+  return (result);
 }
 
 //Return the elapsed time between GNSS measurements in milliseconds, which defines the rate
@@ -9190,7 +9402,11 @@ boolean SFE_UBLOX_GNSS::setNavigationRate(uint16_t rate, uint16_t maxWait)
   payloadCfg[2] = rate & 0xFF; //navRate LSB
   payloadCfg[3] = rate >> 8;   //navRate MSB
 
-  return ((sendCommand(&packetCfg, maxWait)) == SFE_UBLOX_STATUS_DATA_SENT); // We are only expecting an ACK
+  boolean result = ((sendCommand(&packetCfg, maxWait)) == SFE_UBLOX_STATUS_DATA_SENT); // We are only expecting an ACK
+
+  flushCFGRATE(); // Mark the polled measurement and navigation rate data as stale
+
+  return (result);
 }
 
 //Return the ratio between the number of measurements and the number of navigation solutions. Unit is cycles
@@ -9208,6 +9424,13 @@ uint16_t SFE_UBLOX_GNSS::getNavigationRate(uint16_t maxWait)
   return (packetUBXCFGRATE->data.navRate);
 }
 
+//Mark the CFG RATE data as read/stale
+void SFE_UBLOX_GNSS::flushCFGRATE()
+{
+  if (packetUBXCFGRATE == NULL) return; // Bail if RAM has not been allocated (otherwise we could be writing anywhere!)
+  packetUBXCFGRATE->moduleQueried.moduleQueried.all = 0; //Mark all datums as stale (read before)
+}
+
 // ***** DOP Helper Functions
 
 uint16_t SFE_UBLOX_GNSS::getGeometricDOP(uint16_t maxWait)
@@ -10160,6 +10383,45 @@ float SFE_UBLOX_GNSS::getSurveyInMeanAccuracy(uint16_t maxWait) // Returned as m
   return (((float)tempFloat) / 10000.0); //Convert 0.1mm to m
 }
 
+// ***** TIMELS Helper Functions
+
+uint8_t SFE_UBLOX_GNSS::getLeapIndicator(int32_t& timeToLsEvent, uint16_t maxWait)
+{
+  if (packetUBXNAVTIMELS == NULL) initPacketUBXNAVTIMELS(); //Check that RAM has been allocated for the TIMELS data
+  if (packetUBXNAVTIMELS == NULL) //Bail if the RAM allocation failed
+    return 3;
+
+  if (packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.validTimeToLsEvent == false)
+    getLeapSecondEvent(maxWait);
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.validTimeToLsEvent = false; //Since we are about to give this to user, mark this data as stale
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.lsChange = false;
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.timeToLsEvent = false;  
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.all = false;
+  timeToLsEvent = packetUBXNAVTIMELS->data.timeToLsEvent;
+  // returns NTP Leap Indicator
+  // 0 -no warning
+  // 1 -last minute of the day has 61 seconds
+  // 2 -last minute of the day has 59 seconds
+  // 3 -unknown (clock unsynchronized)
+  return ((boolean)packetUBXNAVTIMELS->data.valid.bits.validTimeToLsEvent ? (uint8_t)(packetUBXNAVTIMELS->data.lsChange == -1 ? 2 : packetUBXNAVTIMELS->data.lsChange) : 3);
+}
+
+int8_t SFE_UBLOX_GNSS::getCurrentLeapSeconds(sfe_ublox_ls_src_e& source, uint16_t maxWait)
+{
+  if (packetUBXNAVTIMELS == NULL) initPacketUBXNAVTIMELS(); //Check that RAM has been allocated for the TIMELS data
+  if (packetUBXNAVTIMELS == NULL) //Bail if the RAM allocation failed
+    return false;
+
+  if (packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.validCurrLs == false)
+    getLeapSecondEvent(maxWait);
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.validCurrLs = false; //Since we are about to give this to user, mark this data as stale
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.srcOfCurrLs = false;
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.currLs = false;
+  packetUBXNAVTIMELS->moduleQueried.moduleQueried.bits.all = false;
+  source = ((sfe_ublox_ls_src_e)packetUBXNAVTIMELS->data.srcOfCurrLs);
+  return ((int8_t)packetUBXNAVTIMELS->data.currLs);
+}
+
 // ***** RELPOSNED Helper Functions and automatic support
 
 float SFE_UBLOX_GNSS::getRelPosN(uint16_t maxWait) // Returned as m
diff --git a/src/SparkFun_u-blox_GNSS_Arduino_Library.h b/src/SparkFun_u-blox_GNSS_Arduino_Library.h
index 8e8ab2d..5bfd0e6 100644
--- a/src/SparkFun_u-blox_GNSS_Arduino_Library.h
+++ b/src/SparkFun_u-blox_GNSS_Arduino_Library.h
@@ -99,6 +99,69 @@ typedef enum
 	SFE_UBLOX_PACKET_PACKETAUTO
 } sfe_ublox_packet_buffer_e;
 
+// Define a struct to allow selective logging / processing of NMEA messages
+// Set the individual bits to pass the NMEA messages to the file buffer and/or processNMEA
+// Setting bits.all will pass all messages to the file buffer and processNMEA
+typedef struct
+{
+	union
+	{
+		uint32_t all;
+		struct
+		{
+			uint32_t all : 1;
+			uint32_t UBX_NMEA_DTM : 1;
+			uint32_t UBX_NMEA_GAQ : 1;
+			uint32_t UBX_NMEA_GBQ : 1;
+			uint32_t UBX_NMEA_GBS : 1;
+			uint32_t UBX_NMEA_GGA : 1;
+			uint32_t UBX_NMEA_GLL : 1;
+			uint32_t UBX_NMEA_GLQ : 1;
+			uint32_t UBX_NMEA_GNQ : 1;
+			uint32_t UBX_NMEA_GNS : 1;
+			uint32_t UBX_NMEA_GPQ : 1;
+			uint32_t UBX_NMEA_GQQ : 1;
+			uint32_t UBX_NMEA_GRS : 1;
+			uint32_t UBX_NMEA_GSA : 1;
+			uint32_t UBX_NMEA_GST : 1;
+			uint32_t UBX_NMEA_GSV : 1;
+			uint32_t UBX_NMEA_RLM : 1;
+			uint32_t UBX_NMEA_RMC : 1;
+			uint32_t UBX_NMEA_TXT : 1;
+			uint32_t UBX_NMEA_VLW : 1;
+			uint32_t UBX_NMEA_VTG : 1;
+			uint32_t UBX_NMEA_ZDA : 1;
+		} bits;
+	};
+} sfe_ublox_nmea_filtering_t;
+
+// Define an enum to make it easy to enable/disable selected NMEA messages for logging / processing
+typedef enum
+{
+	SFE_UBLOX_FILTER_NMEA_ALL = 0x00000001,
+	SFE_UBLOX_FILTER_NMEA_DTM = 0x00000002,
+	SFE_UBLOX_FILTER_NMEA_GAQ = 0x00000004,
+	SFE_UBLOX_FILTER_NMEA_GBQ = 0x00000008,
+	SFE_UBLOX_FILTER_NMEA_GBS = 0x00000010,
+	SFE_UBLOX_FILTER_NMEA_GGA = 0x00000020,
+	SFE_UBLOX_FILTER_NMEA_GLL = 0x00000040,
+	SFE_UBLOX_FILTER_NMEA_GLQ = 0x00000080,
+	SFE_UBLOX_FILTER_NMEA_GNQ = 0x00000100,
+	SFE_UBLOX_FILTER_NMEA_GNS = 0x00000200,
+	SFE_UBLOX_FILTER_NMEA_GPQ = 0x00000400,
+	SFE_UBLOX_FILTER_NMEA_GQQ = 0x00000800,
+	SFE_UBLOX_FILTER_NMEA_GRS = 0x00001000,
+	SFE_UBLOX_FILTER_NMEA_GSA = 0x00002000,
+	SFE_UBLOX_FILTER_NMEA_GST = 0x00004000,
+	SFE_UBLOX_FILTER_NMEA_GSV = 0x00008000,
+	SFE_UBLOX_FILTER_NMEA_RLM = 0x00010000,
+	SFE_UBLOX_FILTER_NMEA_RMC = 0x00020000,
+	SFE_UBLOX_FILTER_NMEA_TXT = 0x00040000,
+	SFE_UBLOX_FILTER_NMEA_VLW = 0x00080000,
+	SFE_UBLOX_FILTER_NMEA_VTG = 0x00100000,
+	SFE_UBLOX_FILTER_NMEA_ZDA = 0x00200000
+} sfe_ublox_nmea_filtering_e;
+
 //Registers
 const uint8_t UBX_SYNCH_1 = 0xB5;
 const uint8_t UBX_SYNCH_2 = 0x62;
@@ -159,7 +222,7 @@ const uint8_t UBX_CFG_VALSET = 0x8A;	//Used for config of higher version u-blox
 
 //Class: NMEA
 //The following are used to enable NMEA messages. Descriptions come from the NMEA messages overview in the ZED-F9P Interface Description
-const uint8_t UBX_NMEA_MSB = 0xF0;	//All NMEA enable commands have 0xF0 as MSB
+const uint8_t UBX_NMEA_MSB = 0xF0;	//All NMEA enable commands have 0xF0 as MSB. Equal to UBX_CLASS_NMEA
 const uint8_t UBX_NMEA_DTM = 0x0A;	//GxDTM (datum reference)
 const uint8_t UBX_NMEA_GAQ = 0x45;	//GxGAQ (poll a standard message (if the current talker ID is GA))
 const uint8_t UBX_NMEA_GBQ = 0x44;	//GxGBQ (poll a standard message (if the current Talker ID is GB))
@@ -169,11 +232,13 @@ const uint8_t UBX_NMEA_GLL = 0x01;	//GxGLL (latitude and long, whith time of pos
 const uint8_t UBX_NMEA_GLQ = 0x43;	//GxGLQ (poll a standard message (if the current Talker ID is GL))
 const uint8_t UBX_NMEA_GNQ = 0x42;	//GxGNQ (poll a standard message (if the current Talker ID is GN))
 const uint8_t UBX_NMEA_GNS = 0x0D;	//GxGNS (GNSS fix data)
-const uint8_t UBX_NMEA_GPQ = 0x040; //GxGPQ (poll a standard message (if the current Talker ID is GP))
+const uint8_t UBX_NMEA_GPQ = 0x40;	//GxGPQ (poll a standard message (if the current Talker ID is GP))
+const uint8_t UBX_NMEA_GQQ = 0x47;	//GxGQQ (poll a standard message (if the current Talker ID is GQ))
 const uint8_t UBX_NMEA_GRS = 0x06;	//GxGRS (GNSS range residuals)
 const uint8_t UBX_NMEA_GSA = 0x02;	//GxGSA (GNSS DOP and Active satellites)
 const uint8_t UBX_NMEA_GST = 0x07;	//GxGST (GNSS Pseudo Range Error Statistics)
 const uint8_t UBX_NMEA_GSV = 0x03;	//GxGSV (GNSS satellites in view)
+const uint8_t UBX_NMEA_RLM = 0x0B;	//GxRMC (Return link message (RLM))
 const uint8_t UBX_NMEA_RMC = 0x04;	//GxRMC (Recommended minimum data)
 const uint8_t UBX_NMEA_TXT = 0x41;	//GxTXT (text transmission)
 const uint8_t UBX_NMEA_VLW = 0x0F;	//GxVLW (dual ground/water distance)
@@ -407,6 +472,20 @@ enum sfe_ublox_gnss_ids_e
 	SFE_UBLOX_GNSS_ID_GLONASS
 };
 
+// The GNSS identifiers of leap second event info source - used by UBX-NAV-TIMELS
+enum sfe_ublox_ls_src_e
+{
+	SFE_UBLOX_LS_SRC_DEFAULT,
+	SFE_UBLOX_LS_SRC_GLONASS,
+	SFE_UBLOX_LS_SRC_GPS,
+	SFE_UBLOX_LS_SRC_SBAS,
+	SFE_UBLOX_LS_SRC_BEIDOU,
+	SFE_UBLOX_LS_SRC_GALILEO,
+	SFE_UBLOX_LS_SRC_AIDED,
+	SFE_UBLOX_LS_SRC_CONFIGURED,
+	SFE_UBLOX_LS_SRC_UNKNOWN = 255
+};
+
 #ifndef MAX_PAYLOAD_SIZE
 // v2.0: keep this for backwards-compatibility, but this is largely superseded by setPacketCfgPayloadSize
 #define MAX_PAYLOAD_SIZE 256 //We need ~220 bytes for getProtocolVersion on most ublox modules
@@ -580,15 +659,15 @@ class SFE_UBLOX_GNSS
 	boolean setPortOutput(uint8_t portID, uint8_t comSettings, uint16_t maxWait = defaultMaxWait); //Configure a given port to output UBX, NMEA, RTCM3 or a combination thereof
 	boolean setPortInput(uint8_t portID, uint8_t comSettings, uint16_t maxWait = defaultMaxWait);  //Configure a given port to input UBX, NMEA, RTCM3 or a combination thereof
 
-	boolean setI2CAddress(uint8_t deviceAddress, uint16_t maxTime = defaultMaxWait);										 //Changes the I2C address of the u-blox module
+	boolean setI2CAddress(uint8_t deviceAddress, uint16_t maxTime = defaultMaxWait);			   //Changes the I2C address of the u-blox module
 	void setSerialRate(uint32_t baudrate, uint8_t uartPort = COM_PORT_UART1, uint16_t maxTime = defaultMaxWait); //Changes the serial baud rate of the u-blox module, uartPort should be COM_PORT_UART1/2
 
 	boolean setI2COutput(uint8_t comSettings, uint16_t maxWait = defaultMaxWait);				//Configure I2C port to output UBX, NMEA, RTCM3 or a combination thereof
-	boolean setUART1Output(uint8_t comSettings, uint16_t maxWait = defaultMaxWait); //Configure UART1 port to output UBX, NMEA, RTCM3 or a combination thereof
-	boolean setUART2Output(uint8_t comSettings, uint16_t maxWait = defaultMaxWait); //Configure UART2 port to output UBX, NMEA, RTCM3 or a combination thereof
+	boolean setUART1Output(uint8_t comSettings, uint16_t maxWait = defaultMaxWait);				//Configure UART1 port to output UBX, NMEA, RTCM3 or a combination thereof
+	boolean setUART2Output(uint8_t comSettings, uint16_t maxWait = defaultMaxWait);				//Configure UART2 port to output UBX, NMEA, RTCM3 or a combination thereof
 	boolean setUSBOutput(uint8_t comSettings, uint16_t maxWait = defaultMaxWait);				//Configure USB port to output UBX, NMEA, RTCM3 or a combination thereof
 	boolean setSPIOutput(uint8_t comSettings, uint16_t maxWait = defaultMaxWait);				//Configure SPI port to output UBX, NMEA, RTCM3 or a combination thereof
-	void setNMEAOutputPort(Stream &nmeaOutputPort);																 //Sets the internal variable for the port to direct NMEA characters to
+	void setNMEAOutputPort(Stream &nmeaOutputPort);												//Sets the internal variable for the port to direct NMEA characters to
 
 	//Reset to defaults
 
@@ -800,6 +879,9 @@ class SFE_UBLOX_GNSS
 	// Add "auto" support for NAV SVIN - to avoid needing 'global' storage
 	boolean getSurveyStatus(uint16_t maxWait); //Reads survey in status
 
+	// Add "auto" support for NAV TIMELS - to avoid needing 'global' storage
+	boolean getLeapSecondEvent(uint16_t maxWait); //Reads leap second event info
+
 	boolean getRELPOSNED(uint16_t maxWait = defaultMaxWait); //Get Relative Positioning Information of the NED frame
 	boolean setAutoRELPOSNED(boolean enabled, uint16_t maxWait = defaultMaxWait); //Enable/disable automatic RELPOSNED reports
 	boolean setAutoRELPOSNED(boolean enabled, boolean implicitUpdate, uint16_t maxWait = defaultMaxWait); //Enable/disable automatic RELPOSNED, with implicitUpdate == false accessing stale data will not issue parsing of data in the rxbuffer of your interface, instead you have to call checkUblox when you want to perform an update
@@ -928,6 +1010,14 @@ class SFE_UBLOX_GNSS
 	void flushHNRPVT(); //Mark all the data as read/stale
 	void logHNRPVT(boolean enabled = true); // Log data to file buffer
 
+	// Helper functions for NMEA logging
+	void setNMEALoggingMask(uint32_t messages = SFE_UBLOX_FILTER_NMEA_ALL); // Add selected NMEA messages to file buffer - if enabled. Default to adding ALL messages to the file buffer
+	uint32_t getNMEALoggingMask(); // Return which NMEA messages are selected for logging to the file buffer - if enabled
+
+	// Helper functions to control which NMEA messages are passed to processNMEA
+	void setProcessNMEAMask(uint32_t messages = SFE_UBLOX_FILTER_NMEA_ALL); // Control which NMEA messages are passed to processNMEA. Default to passing ALL messages
+	uint32_t getProcessNMEAMask(); // Return which NMEA messages are passed to processNMEA
+
 	// Helper functions for CFG RATE
 
 	boolean setNavigationFrequency(uint8_t navFreq, uint16_t maxWait = defaultMaxWait);	//Set the number of nav solutions sent per second
@@ -936,6 +1026,7 @@ class SFE_UBLOX_GNSS
 	uint16_t getMeasurementRate(uint16_t maxWait = defaultMaxWait);					 	//Return the elapsed time between GNSS measurements in milliseconds
 	boolean setNavigationRate(uint16_t rate, uint16_t maxWait = defaultMaxWait);		//Set the ratio between the number of measurements and the number of navigation solutions. Unit is cycles. Max is 127
 	uint16_t getNavigationRate(uint16_t maxWait = defaultMaxWait);					 	//Return the ratio between the number of measurements and the number of navigation solutions. Unit is cycles
+	void flushCFGRATE(); // Mark the measurement and navigation rate data as stale - used by the set rate functions
 
 	// Helper functions for DOP
 
@@ -1028,6 +1119,11 @@ class SFE_UBLOX_GNSS
 	uint16_t getSurveyInObservationTime(uint16_t maxWait = defaultMaxWait); // Truncated to 65535 seconds
 	float getSurveyInMeanAccuracy(uint16_t maxWait = defaultMaxWait); // Returned as m
 
+	// Helper functions for TIMELS
+
+	uint8_t getLeapIndicator(int32_t& timeToLsEvent, uint16_t maxWait = defaultMaxWait);
+	int8_t getCurrentLeapSeconds(sfe_ublox_ls_src_e& source, uint16_t maxWait = defaultMaxWait);
+
 	// Helper functions for RELPOSNED
 
 	float getRelPosN(uint16_t maxWait = defaultMaxWait); // Returned as m
@@ -1080,6 +1176,7 @@ class SFE_UBLOX_GNSS
 	UBX_NAV_HPPOSECEF_t *packetUBXNAVHPPOSECEF = NULL; // Pointer to struct. RAM will be allocated for this if/when necessary
 	UBX_NAV_HPPOSLLH_t *packetUBXNAVHPPOSLLH = NULL; // Pointer to struct. RAM will be allocated for this if/when necessary
 	UBX_NAV_CLOCK_t *packetUBXNAVCLOCK = NULL; // Pointer to struct. RAM will be allocated for this if/when necessary
+	UBX_NAV_TIMELS_t *packetUBXNAVTIMELS = NULL; // Pointer to struct. RAM will be allocated for this if/when necessary
 	UBX_NAV_SVIN_t *packetUBXNAVSVIN = NULL; // Pointer to struct. RAM will be allocated for this if/when necessary
 	UBX_NAV_RELPOSNED_t *packetUBXNAVRELPOSNED = NULL; // Pointer to struct. RAM will be allocated for this if/when necessary
 
@@ -1153,6 +1250,7 @@ class SFE_UBLOX_GNSS
 	boolean initPacketUBXNAVHPPOSECEF(); // Allocate RAM for packetUBXNAVHPPOSECEF and initialize it
 	boolean initPacketUBXNAVHPPOSLLH(); // Allocate RAM for packetUBXNAVHPPOSLLH and initialize it
 	boolean initPacketUBXNAVCLOCK(); // Allocate RAM for packetUBXNAVCLOCK and initialize it
+	boolean initPacketUBXNAVTIMELS(); // Allocate RAM for packetUBXNAVTIMELS and initialize it
 	boolean initPacketUBXNAVSVIN(); // Allocate RAM for packetUBXNAVSVIN and initialize it
 	boolean initPacketUBXNAVRELPOSNED(); // Allocate RAM for packetUBXNAVRELPOSNED and initialize it
 	boolean initPacketUBXRXMSFRBX(); // Allocate RAM for packetUBXRXMSFRBX and initialize it
@@ -1182,6 +1280,9 @@ class SFE_UBLOX_GNSS
 
 	boolean ubx7FcheckDisabled = false; // Flag to indicate if the "7F" check should be ignored in checkUbloxI2C
 
+	sfe_ublox_nmea_filtering_t _logNMEA; // Flags to indicate which NMEA messages should be added to the file buffer for logging
+	sfe_ublox_nmea_filtering_t _processNMEA; // Flags to indicate which NMEA messages should be passed to processNMEA
+
 	//The packet buffers
 	//These are pointed at from within the ubxPacket
 	uint8_t payloadAck[2];				  // Holds the requested ACK/NACK
@@ -1212,11 +1313,16 @@ class SFE_UBLOX_GNSS
 
 	unsigned long lastCheck = 0;
 
-	uint16_t ubxFrameCounter;			  //It counts all UBX frame. [Fixed header(2bytes), CLS(1byte), ID(1byte), length(2bytes), payload(x bytes), checksums(2bytes)]
-
+	uint16_t ubxFrameCounter; //Count all UBX frame bytes. [Fixed header(2bytes), CLS(1byte), ID(1byte), length(2bytes), payload(x bytes), checksums(2bytes)]
 	uint8_t rollingChecksumA; //Rolls forward as we receive incoming bytes. Checked against the last two A/B checksum bytes
 	uint8_t rollingChecksumB; //Rolls forward as we receive incoming bytes. Checked against the last two A/B checksum bytes
 
+	int8_t nmeaByteCounter;				//Count all NMEA message bytes.
+	const int8_t maxNMEAByteCount = 82;	// Abort NMEA message reception if nmeaByteCounter exceeds this (https://en.wikipedia.org/wiki/NMEA_0183#Message_structure)
+	uint8_t nmeaAddressField[6];		// NMEA Address Field - includes the start character (*)
+	boolean logThisNMEA();				// Return true if we should log this NMEA message
+	boolean processThisNMEA();			// Return true if we should pass this NMEA message to processNMEA
+
 	uint16_t rtcmLen = 0;
 
 	// Flag to prevent reentry into checkCallbacks
diff --git a/src/u-blox_structs.h b/src/u-blox_structs.h
index 50611bf..a8a8300 100644
--- a/src/u-blox_structs.h
+++ b/src/u-blox_structs.h
@@ -854,6 +854,66 @@ typedef struct
   UBX_NAV_CLOCK_data_t  *callbackData;
 } UBX_NAV_CLOCK_t;
 
+// UBX-NAV-TIMELS (0x01 0x26): Leap second event information
+const uint16_t UBX_NAV_TIMELS_LEN = 24;
+
+typedef struct
+{
+  uint32_t iTOW; // GPS time of week of the navigation epoch: ms
+  uint8_t version; // Message version (0x00 for this version)
+  uint8_t reserved1[3];
+  uint8_t srcOfCurrLs; //Information source for the current number of leap seconds
+  int8_t currLs; //Current number of leap seconds since start of GPS (Jan 6, 1980), s
+  uint8_t srcOfLsChange; //Information source for the future leap second event
+  int8_t lsChange; //Future leap second change if one is scheduled, +1, 0, -1s
+  int32_t timeToLsEvent; //Num of secs until the next or from the last leap second, s
+  uint16_t dateOfLsGpsWn; //GPS week num (WN) of the next or the last leap second event
+  uint16_t dateOfLsGpsDn; //GPS day of week num (DN) for the next or last leap second event
+  uint8_t reserved2[3];
+  union
+  {
+    uint8_t all;
+    struct
+    {
+      uint8_t validCurrLs : 1; // 1 = Valid current number of leap seconds value
+      uint8_t validTimeToLsEvent : 1; // 1 = Valid time to next leap second event or from the last leap second event if no future event scheduled
+    } bits;
+  } valid;
+} UBX_NAV_TIMELS_data_t;
+
+typedef struct
+{
+  union
+  {
+    uint32_t all;
+    struct
+    {
+      uint32_t all : 1;
+
+      uint32_t iTOW : 1;
+      uint32_t version : 1;
+      uint32_t srcOfCurrLs : 1;
+      uint32_t currLs : 1;
+      uint32_t srcOfLsChange : 1;
+      uint32_t lsChange : 1;
+      uint32_t timeToLsEvent : 1;
+      uint32_t dateOfLsGpsWn : 1;
+      uint32_t dateOfLsGpsDn : 1;
+      uint32_t validCurrLs : 1;
+      uint32_t validTimeToLsEvent : 1;
+    } bits;
+  } moduleQueried;
+} UBX_NAV_TIMELS_moduleQueried_t;
+
+typedef struct
+{
+	ubxAutomaticFlags automaticFlags;
+  UBX_NAV_TIMELS_data_t data;
+  UBX_NAV_TIMELS_moduleQueried_t moduleQueried;
+  void (*callbackPointer)(UBX_NAV_TIMELS_data_t);
+  UBX_NAV_TIMELS_data_t  *callbackData;
+} UBX_NAV_TIMELS_t;
+
 // UBX-NAV-SVIN (0x01 0x3B): Survey-in data
 const uint16_t UBX_NAV_SVIN_LEN = 40;