diff --git a/ChangeLog b/ChangeLog
index f87cff5..b2ce32b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+2017.283: 3.8
+	- Update libmseed to 2.19.5, with fix for leap second calculation.
+
 2017.136: 3.7
 	- Update libmseed to 2.19.4.
 	- Remove Windows/Watcom build files and documentation, this will not build
diff --git a/libmseed/ChangeLog b/libmseed/ChangeLog
index 8c766f1..7f8e09d 100644
--- a/libmseed/ChangeLog
+++ b/libmseed/ChangeLog
@@ -1,3 +1,10 @@
+2017.283: 2.19.5
+	- msr_endtime(): calculate correct end time during a leap second.
+	- Fixed signedness comparison warning.
+
+2017.125:
+	- Export LM_SIZEOF_OFF_T on Windows via libmseed.def.
+
 2017.118: 2.19.4
 	- Add global LM_SIZEOF_OFF_T variable that is set to the size of
 	the off_t data type as determined at compile time.
diff --git a/libmseed/README.md b/libmseed/README.md
index 1a7cb33..7324df4 100644
--- a/libmseed/README.md
+++ b/libmseed/README.md
@@ -56,3 +56,5 @@ in the ChangeLog.
 
 This library also uses code bits published in the public domain and
 acknowledgement is included in the code whenever possible.
+
+With software provided by http://2038bug.com/ (site offline, checked Oct. 2017)
diff --git a/libmseed/doc/ms_time.3 b/libmseed/doc/ms_time.3
index 5c5c367..d9d1c63 100644
--- a/libmseed/doc/ms_time.3
+++ b/libmseed/doc/ms_time.3
@@ -191,6 +191,10 @@ values.
 A special value defined as HPTERROR in libmseed.h is used to represent
 errors for routines returning hptime.
 
+.SH ACKNOWLEDGEMENTS
+
+With software provided by http://2038bug.com/ (site offline, checked Oct. 2017)
+
 .SH AUTHOR
 .nf
 Chad Trabant
diff --git a/libmseed/libmseed.def b/libmseed/libmseed.def
index f415164..4be57c3 100644
--- a/libmseed/libmseed.def
+++ b/libmseed/libmseed.def
@@ -102,3 +102,4 @@ EXPORTS
    ms_gswap2a
    ms_gswap4a
    ms_gswap8a
+   LM_SIZEOF_OFF_T
diff --git a/libmseed/libmseed.h b/libmseed/libmseed.h
index 87adb84..f708dc0 100644
--- a/libmseed/libmseed.h
+++ b/libmseed/libmseed.h
@@ -28,8 +28,8 @@
 extern "C" {
 #endif
 
-#define LIBMSEED_VERSION "2.19.4"
-#define LIBMSEED_RELEASE "2017.118"
+#define LIBMSEED_VERSION "2.19.5"
+#define LIBMSEED_RELEASE "2017.283"
 
 /* C99 standard headers */
 #include <stdlib.h>
diff --git a/libmseed/msrutils.c b/libmseed/msrutils.c
index 314f02d..76a66ff 100644
--- a/libmseed/msrutils.c
+++ b/libmseed/msrutils.c
@@ -7,7 +7,7 @@
  *   ORFEUS/EC-Project MEREDIAN
  *   IRIS Data Management Center
  *
- * modified: 2016.286
+ * modified: 2016.283
  ***************************************************************************/
 
 #include <stdio.h>
@@ -571,6 +571,14 @@ msr_starttime_uc (MSRecord *msr)
  * actual last sample time and *not* the time "covered" by the last
  * sample.
  *
+ * On the epoch time scale the value of a leap second is the same as
+ * the second following the leap second, without external information
+ * the values are ambiguous.
+ *
+ * Leap second handling: when a record completely contains a leap
+ * second, starts before and ends after, the calculated end time will
+ * be adjusted (reduced) by one second.
+ *
  * Returns the time of the last sample as a high precision epoch time
  * on success and HPTERROR on error.
  ***************************************************************************/
@@ -592,7 +600,7 @@ msr_endtime (MSRecord *msr)
     while (lslist)
     {
       if (lslist->leapsecond > msr->starttime &&
-          lslist->leapsecond < (msr->starttime + span))
+          lslist->leapsecond <= (msr->starttime + span - HPTMODULUS))
       {
         span -= HPTMODULUS;
         break;
diff --git a/libmseed/unpackdata.c b/libmseed/unpackdata.c
index 3ef84a2..24d30ff 100644
--- a/libmseed/unpackdata.c
+++ b/libmseed/unpackdata.c
@@ -3,7 +3,7 @@
  * STEIM2, GEOSCOPE (24bit and gain ranged), CDSN, SRO and DWWSSN
  * encoded data.
  *
- * modified: 2017.053
+ * modified: 2017.283
  ************************************************************************/
 
 #include <memory.h>
@@ -628,7 +628,7 @@ msr_decode_geoscope (char *input, int samplecount, float *output,
       mantissa = sample32.i;
 
       /* Take 2's complement for mantissa for overflow */
-      if (mantissa > MAX24)
+      if ((unsigned long)mantissa > MAX24)
         mantissa -= 2 * (MAX24 + 1);
 
       /* Store */
@@ -851,7 +851,7 @@ msr_decode_sro (int16_t *input, int samplecount, int32_t *output,
     gainrange = (sint & SRO_GAINRANGE_MASK) >> SRO_SHIFT;
 
     /* Take 2's complement for mantissa */
-    if (mantissa > MAX12)
+    if ((unsigned long)mantissa > MAX12)
       mantissa -= 2 * (MAX12 + 1);
 
     /* Calculate exponent, SRO exponent = 0..10 */
@@ -902,7 +902,7 @@ msr_decode_dwwssn (int16_t *input, int samplecount, int32_t *output,
     sample = (int32_t)sint;
 
     /* Take 2's complement for sample */
-    if (sample > MAX16)
+    if ((unsigned long)sample > MAX16)
       sample -= 2 * (MAX16 + 1);
 
     /* Save sample in output array */
diff --git a/src/msi.c b/src/msi.c
index fa82356..327532f 100644
--- a/src/msi.c
+++ b/src/msi.c
@@ -31,7 +31,7 @@ static int addfile (char *filename);
 static int addlistfile (char *filename);
 static void usage (void);
 
-#define VERSION "3.7"
+#define VERSION "3.8"
 #define PACKAGE "msi"
 
 static flag    verbose      = 0;