diff --git a/library.properties b/library.properties
index 0a5a6a5..cef0eb9 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=SparkFun u-blox GNSS Arduino Library
-version=2.2.0
+version=2.2.1
 author=SparkFun Electronics <techsupport@sparkfun.com>
 maintainer=SparkFun Electronics <sparkfun.com>
 sentence=Library for I2C, Serial and SPI 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 5eb04af..952f79f 100644
--- a/src/SparkFun_u-blox_GNSS_Arduino_Library.cpp
+++ b/src/SparkFun_u-blox_GNSS_Arduino_Library.cpp
@@ -3265,8 +3265,12 @@ void SFE_UBLOX_GNSS::processUBXpacket(ubxPacket *msg)
     // Note: length is variable with version 0x01
     // Note: the field positions depend on the version
     {
-      // Parse various byte fields into storage - but only if we have memory allocated for it
-      if ((packetUBXRXMPMP != NULL) && (packetUBXRXMPMP->callbackData != NULL))
+      // Parse various byte fields into storage - but only if we have memory allocated for it.
+      // By default, new PMP data will always overwrite 'old' data (data which is valid but which has not yet been read by the callback).
+      // To prevent this, uncomment the line two lines below
+      if ((packetUBXRXMPMP != NULL) && (packetUBXRXMPMP->callbackData != NULL)
+          //&& (packetUBXRXMPMP->automaticFlags.flags.bits.callbackCopyValid == false) // <=== Uncomment this line to prevent new data from overwriting 'old'
+          )
       {
         packetUBXRXMPMP->callbackData->version = extractByte(msg, 0);
         packetUBXRXMPMP->callbackData->numBytesUserData = extractInt(msg, 2);
@@ -3298,8 +3302,12 @@ void SFE_UBLOX_GNSS::processUBXpacket(ubxPacket *msg)
         packetUBXRXMPMP->automaticFlags.flags.bits.callbackCopyValid = true; // Mark the data as valid
       }
 
-      // Full PMP message
-      if ((packetUBXRXMPMPmessage != NULL) && (packetUBXRXMPMPmessage->callbackData != NULL))
+      // Full PMP message, including Class, ID and checksum
+      // By default, new PMP data will always overwrite 'old' data (data which is valid but which has not yet been read by the callback).
+      // To prevent this, uncomment the line two lines below
+      if ((packetUBXRXMPMPmessage != NULL) && (packetUBXRXMPMPmessage->callbackData != NULL)
+          //&& (packetUBXRXMPMPmessage->automaticFlags.flags.bits.callbackCopyValid == false) // <=== Uncomment this line to prevent new data from overwriting 'old'
+          )
       {
         packetUBXRXMPMPmessage->callbackData->sync1 = UBX_SYNCH_1;
         packetUBXRXMPMPmessage->callbackData->sync2 = UBX_SYNCH_2;