diff --git a/1.9/Makefile b/1.9/Makefile
index 666c4740..2436e321 100644
--- a/1.9/Makefile
+++ b/1.9/Makefile
@@ -47,7 +47,7 @@ ifeq ($(SYS), MAC)
   CXXFLAGS += $(MACFLAGS)
   BLASFLAGS ?= -framework Accelerate
   LDFLAGS ?= -ldl
-  ZLIB ?= -L. ../zlib-1.2.13/libz.a
+  ZLIB ?= -L. ../zlib-1.3/libz.a
 endif
 
 ifeq ($(SYS), WIN)
@@ -58,13 +58,13 @@ ifeq ($(SYS), WIN)
 # NO_LAPACK.
   BLASFLAGS ?= -L. lapack/liblapack.a -L. lapack/librefblas.a
   LDFLAGS ?= -lm -static-libgcc
-  ZLIB ?= -L. ../zlib-1.2.13/libz.a
+  ZLIB ?= -L. ../zlib-1.3/libz.a
 endif
 
 # These must appear after the MAC/WIN-specific ?= statements.
 BLASFLAGS ?=	-L/usr/lib64/atlas -llapack -lblas -lcblas -latlas
 LDFLAGS ?=	-lm -lpthread -ldl
-ZLIB ?=		-L. ../zlib-1.2.13/libz.so.1.2.13
+ZLIB ?=		-L. ../zlib-1.3/libz.so.1.3
 
 ifdef NO_LAPACK
   BLASFLAGS=
diff --git a/1.9/Makefile.old b/1.9/Makefile.old
deleted file mode 100644
index 979a2487..00000000
--- a/1.9/Makefile.old
+++ /dev/null
@@ -1,106 +0,0 @@
-# This is a bit of a mess.  Work with Makefile.std instead.
-
-CFLAGS=-Wall -O2
-BLASFLAGS=-L/usr/lib64/atlas -llapack -lcblas -latlas
-BLASFLAGS64=-L/usr/lib64/atlas -llapack -lcblas -latlas
-LINKFLAGS=-lm -lpthread
-ZLIB=../zlib-1.2.12/libz.so.1.2.12
-
-UNAME := $(shell uname)
-ifeq ($(UNAME), Darwin)
-  CFLAGS=-Wall -O2 -mmacosx-version-min=10.7 -stdlib=libc++
-  GCC_GTEQ_43 := $(shell expr `g++ -dumpversion | sed -e 's/\.\([0-9][0-9]\)/\1/g' -e 's/\.\([0-9]\)/0\1/g' -e 's/^[0-9]\{3,4\}$$/&00/'` \>= 40300)
-  ifeq "$(GCC_GTEQ_43)" "1"
-    CFLAGS=-Wall -O2 -flax-vector-conversions -mmacosx-version-min=10.7
-  endif
-  BLASFLAGS=-framework Accelerate
-  BLASFLAGS64=-framework Accelerate
-  LINKFLAGS=-ldl
-  ZLIB=../zlib-1.2.12/libz-32.a
-  ZLIB64=../zlib-1.2.12/libz-64.a
-else
-  ifeq ($(UNAME), MINGW32_NT-6.2)
-    BLASFLAGS=-Wl,-Bstatic -L. lapack/liblapack.a -L. lapack/librefblas.a
-    BLASFLAGS64=-Wl,-Bstatic -L. lapack/liblapack-64.a -L. lapack/librefblas-64.a
-    LINKFLAGS=-lm -static-libgcc
-    ZLIB=../zlib-1.2.12/libz-32.a
-    ZLIB64=../zlib-1.2.12/libz-64.a
-  endif
-endif
-
-CSRC = plink.c plink_assoc.c plink_calc.c plink_cluster.c plink_cnv.c plink_common.c plink_data.c plink_dosage.c plink_family.c plink_filter.c plink_glm.c plink_help.c plink_homozyg.c plink_lasso.c plink_ld.c plink_matrix.c plink_misc.c plink_perm.c plink_rserve.c plink_set.c plink_stats.c SFMT.c dcdflib.c pigz.c yarn.c hfile.c bgzf.c
-
-CCSRC = Rconnection.cc
-
-SRC = $(CSRC) $(CCSRC)
-
-OBJ = $(CSRC:.c=.o) $(CCSRC:.cc=.o)
-
-%.o: %.c
-	g++ -x c++ -c $(CFLAGS) -o $@ $<
-
-%.o: %.cc
-	g++ -x c++ -c $(CFLAGS) -o $@ $<
-
-plink64: $(OBJ)
-	g++ $(CFLAGS) $(OBJ) -o plink $(BLASFLAGS64) $(LINKFLAGS) -L. $(ZLIB64)
-# for clean build, "make clobber" first
-
-plink: $(SRC)
-	g++ -x c++ $(CFLAGS) $(SRC) -m32 -x none -o plink $(BLASFLAGS) $(LINKFLAGS) -L. $(ZLIB)
-
-plinkw: $(SRC)
-	g++ $(CFLAGS) $(SRC) -c
-	gfortran -O2 $(OBJ) -o plink $(BLASFLAGS) $(LINKFLAGS) -L. $(ZLIB)
-
-plinkc: $(SRC)
-	gcc $(CFLAGS) $(CSRC) -std=c99 -m32 -x none -o plink $(BLASFLAGS) $(LINKFLAGS) -L. $(ZLIB)
-
-plinks: $(SRC)
-	g++ $(CFLAGS) $(SRC) -o plink_linux_s -Wl,-Bstatic $(BLASFLAGS) -Wl,-Bdynamic $(LINKFLAGS) -L. $(ZLIB)
-
-plinkd: $(SRC)
-	g++ $(CFLAGS) $(SRC) -o plink_linux $(BLASFLAGS) -Wl,-Bdynamic $(LINKFLAGS) -L. $(ZLIB)
-
-plinknl: $(SRC)
-	g++ $(CFLAGS) $(SRC) -o plink $(LINKFLAGS) -Wl,-Bstatic -L. $(ZLIB)
-
-plink64w: $(SRC)
-	g++ $(CFLAGS) $(SRC) -c
-	gfortran -O2 $(OBJ) -o plink64 $(BLASFLAGS64) $(LINKFLAGS) -L. $(ZLIB64)
-
-plink64c: $(SRC)
-	gcc $(CFLAGS) $(CSRC) -std=c99 -x none -o plink $(BLASFLAGS64) $(LINKFLAGS) -L. $(ZLIB64)
-
-plink64nl: $(SRC)
-	g++ $(CFLAGS) $(SRC) -o plink $(LINKFLAGS) -L. $(ZLIB64)
-
-pigz_test: pigz_test.c pigz.c yarn.c
-	g++ -Wall -O2 pigz_test.c pigz.c yarn.c -o pigz_test -L. $(ZLIB64)
-
-prettify: prettify.c
-	gcc -Wall -O2 prettify.c -o prettify
-
-prettifyw: prettify.c
-	gcc -Wall -O2 prettify.c -o prettify
-
-dbl2txt: dbl2txt.c
-	gcc -Wall -O2 dbl2txt.c -o dbl2txt
-
-nsort: nsort.c
-	gcc -Wall -O2 nsort.c -o nsort
-
-interval_merge: interval_merge.c
-	gcc -Wall -O2 interval_merge.c -o interval_merge
-
-dose2plink32: dose2plink.c
-	g++ -Wall -O2 -lm -m32 dose2plink.c -o dose2plink -L. $(ZLIB)
-
-dose2plink: dose2plink.c
-	g++ -Wall -O2 -lm dose2plink.c -o dose2plink -L. $(ZLIB64)
-
-bgen_to_gen: bgen_to_gen.c plink_common.c SFMT.c pigz.c yarn.c
-	g++ -x c++ -Wall -O2 -DDYNAMIC_ZLIB bgen_to_gen.c plink_common.c SFMT.c pigz.c yarn.c -o bgen_to_gen $(BLASFLAGS64) $(LINKFLAGS) -lz
-
-clobber:
-	rm -f *.o
diff --git a/1.9/Makefile.std b/1.9/Makefile.std
deleted file mode 100644
index 398949db..00000000
--- a/1.9/Makefile.std
+++ /dev/null
@@ -1,104 +0,0 @@
-# General-purpose Makefile for PLINK 1.90
-#
-# Compilation options:
-#   Do not link to LAPACK                    NO_LAPACK
-
-# Leave blank after "=" to disable; put "= 1" to enable
-# (when enabled, "#define NOLAPACK" must be uncommented in plink_common.h)
-NO_LAPACK =
-
-# Variable that allows additional linker flags (e.g., "-L/path/to/libs") to be
-# passed into the linker; to use this, invoke 'make LDFLAGS_EXTRA="<opts>"'.
-LDFLAGS_EXTRA =
-
-.PHONY: clean install
-
-# should autodetect system
-SYS = UNIX
-ifdef SystemRoot
-  SYS = WIN
-else
-  UNAME := $(shell uname)
-  ifeq ($(UNAME), Darwin)
-    SYS = MAC
-  endif
-endif
-
-# Allow these to be overridden by make arguments or env variables, so people
-# don't have to edit the Makefile to build in a different environment.
-BIN ?=		plink
-CC ?=		gcc
-CXX ?=		g++
-CFLAGS ?=	-Wall -O2
-CXXFLAGS ?=	-Wall -O2
-
-PREFIX ?=	/usr/local
-DESTDIR ?=	.
-INSTALL ?=	install
-STRIP ?=	strip
-
-ifeq ($(SYS), MAC)
-  GCC_GTEQ_43 := $(shell expr `g++ -dumpversion | sed -e 's/\.\([0-9][0-9]\)/\1/g' -e 's/\.\([0-9]\)/0\1/g' -e 's/^[0-9]\{3,4\}$$/&00/'` \>= 40300)
-  ifeq "$(GCC_GTEQ_43)" "1"
-    CFLAGS ?= -Wall -O2 -flax-vector-conversions
-  endif
-  BLASFLAGS ?= -framework Accelerate
-  LDFLAGS ?= -ldl
-  ZLIB ?= ../zlib-1.2.12/libz.1.2.12.dylib
-endif
-
-ifeq ($(SYS), WIN)
-# Note that, unlike the Linux and Mac build processes, this STATICALLY links
-# LAPACK, since we have not gotten around to trying dynamically-linked LAPACK
-# on Windows.
-# If you don't already have LAPACK built, you'll probably want to turn on
-# NO_LAPACK.
-  BLASFLAGS ?= -L. lapack/liblapack.a -L. lapack/librefblas.a
-  LDFLAGS ?= -lm -static-libgcc
-  ZLIB ?= ../zlib-1.2.12/libz.a
-endif
-
-# These must appear after the MAC/WIN-specific ?= statements.
-BLASFLAGS ?=	-L/usr/lib64/atlas -llapack -lblas -lcblas -latlas
-LDFLAGS ?=	-lm -lpthread -ldl
-ZLIB ?=		../zlib-1.2.12/libz.so.1.2.12
-
-ifdef NO_LAPACK
-  BLASFLAGS=
-endif
-
-OBJS = plink.o plink_assoc.o plink_calc.o plink_cluster.o plink_cnv.o plink_common.o plink_data.o plink_dosage.o plink_family.o plink_filter.o plink_glm.o plink_help.o plink_homozyg.o plink_lasso.o plink_ld.o plink_matrix.o plink_misc.o plink_perm.o plink_rserve.o plink_set.o plink_stats.o SFMT.o dcdflib.o pigz.o yarn.o Rconnection.o hfile.o bgzf.o
-
-# In the event that you are still concurrently using PLINK 1.07, we suggest
-# renaming that binary to "plink107", and this one to "plink" or "plink1".
-
-all:	$(BIN)
-
-plink: $(OBJS)
-	$(CXX) $(OBJS) $(LDFLAGS_EXTRA) $(BLASFLAGS) $(LDFLAGS) -L. $(ZLIB) -o $@
-
-plinkw: $(OBJS)
-	gfortran -O2 $(OBJS) $(LDFLAGS_EXTRA) -Wl,-Bstatic $(BLASFLAGS) $(LDFLAGS) -L. $(ZLIB) -o $@
-
-install:
-	$(INSTALL) -d $(DESTDIR)$(PREFIX)/bin
-	$(INSTALL) -c $(BIN) $(DESTDIR)$(PREFIX)/bin
-
-install-strip: install
-	$(STRIP) $(DESTDIR)$(PREFIX)/bin/$(BIN)
-
-clean:
-	rm -f $(OBJS) plink plinkw
-
-# Pattern-based rules for compiling object (.o) files; basically identical to
-# GNU make's built-in rules, except we explicitly use "g++" instead of $(CC).
-
-# Compiling C files with a C++ compiler is deprecated, but the code needs
-# to be cleaned up before we can switch to cc.  E.g. plink_rserve.c
-# includes a C++ header and exposed functions will need to be declared with
-# extern "C".
-%.o: %.c
-	$(CXX) -c $(CPPFLAGS) $(CFLAGS) $< -o $@
-
-%.o: %.cc
-	$(CXX) -x c++ -c $(CPPFLAGS) $(CXXFLAGS) $< -o $@
diff --git a/1.9/build_mac/Makefile b/1.9/build_mac/Makefile
index 2a3f76f7..7d7f3439 100644
--- a/1.9/build_mac/Makefile
+++ b/1.9/build_mac/Makefile
@@ -25,8 +25,8 @@ ifeq ($(SYS), MAC)
   CXXFLAGS += $(MACFLAGS)
   BLASFLAGS ?= -framework Accelerate
   LDFLAGS ?= -ldl
-  ZLIB_AMD ?= -L. ../../zlib-1.2.13/libz-amd64.a
-  ZLIB_ARM ?= -L. ../../zlib-1.2.13/libz-arm64.a
+  ZLIB_AMD ?= -L. ../../zlib-1.3/libz-amd64.a
+  ZLIB_ARM ?= -L. ../../zlib-1.3/libz-arm64.a
 endif
 
 CCSRC = plink.c plink_assoc.c plink_calc.c plink_cluster.c plink_cnv.c plink_common.c plink_data.c plink_dosage.c plink_family.c plink_filter.c plink_glm.c plink_help.c plink_homozyg.c plink_lasso.c plink_ld.c plink_matrix.c plink_misc.c plink_perm.c plink_rserve.c plink_set.c plink_stats.c SFMT.c dcdflib.c pigz.c yarn.c Rconnection.cc hfile.c bgzf.c
diff --git a/1.9/dose2plink.c b/1.9/dose2plink.c
index 8ebe407e..3ccb5a22 100644
--- a/1.9/dose2plink.c
+++ b/1.9/dose2plink.c
@@ -96,7 +96,7 @@
   #endif
 #endif
 
-#include "../zlib-1.2.13/zlib.h"
+#include "../zlib-1.3/zlib.h"
 
 #ifdef __APPLE__
   #include <sys/sysctl.h>
diff --git a/1.9/pigz.c b/1.9/pigz.c
index e695ca8d..58913a58 100644
--- a/1.9/pigz.c
+++ b/1.9/pigz.c
@@ -300,7 +300,7 @@
 #ifdef DYNAMIC_ZLIB
   #include <zlib.h>
 #else
-  #include "../zlib-1.2.13/zlib.h"
+  #include "../zlib-1.3/zlib.h"
 #endif
 
 #include "pigz.h"
@@ -526,7 +526,7 @@ int32_t flex_pzwrite_close_null(Pigz_state* ps_ptr, char* writep) {
 #ifdef DYNAMIC_ZLIB
   #include <zlib.h>
 #else
-  #include "../zlib-1.2.13/zlib.h" /* deflateInit2(), deflateReset(), deflate(), */
+  #include "../zlib-1.3/zlib.h" /* deflateInit2(), deflateReset(), deflate(), */
                         /* deflateEnd(), deflateSetDictionary(), crc32(),
                            inflateBackInit(), inflateBack(), inflateBackEnd(),
                            Z_DEFAULT_COMPRESSION, Z_DEFAULT_STRATEGY,
diff --git a/1.9/plink.c b/1.9/plink.c
index cd6b28cb..ce7f2b3d 100644
--- a/1.9/plink.c
+++ b/1.9/plink.c
@@ -105,10 +105,10 @@ static const char ver_str[] =
 #else
   " 32-bit"
 #endif
-  " (13 Feb 2023)";
+  " (6 Sep 2023)";
 static const char ver_str2[] =
   // include leading space if day < 10, so character length stays the same
-  ""
+  " "
 #ifdef STABLE_BUILD
   " " // (don't want this when version number has two trailing digits)
 #else
diff --git a/1.9/plink_calc.c b/1.9/plink_calc.c
index e1a9c0a3..d93a5d85 100644
--- a/1.9/plink_calc.c
+++ b/1.9/plink_calc.c
@@ -5442,7 +5442,6 @@ int32_t rel_cutoff_batch(uint32_t load_grm_bin, char* grmname, char* outname, ch
   uint32_t uii;
   uint32_t row;
   uint32_t col;
-  uint32_t new_row;
   uint32_t pct;
   uintptr_t sample_idx;
   int32_t* rel_ct_arr;
@@ -5862,7 +5861,6 @@ int32_t rel_cutoff_batch(uint32_t load_grm_bin, char* grmname, char* outname, ch
       pct = 1;
       row = 0;
       col = 0;
-      new_row = 1;
       progress = 0;
       hundredth = 1 + ((((uint64_t)sample_ct) * (sample_ct - 1)) / 200);
       memcpy(outname_end, ".grm.N.bin", 11);
@@ -5923,7 +5921,6 @@ int32_t rel_cutoff_batch(uint32_t load_grm_bin, char* grmname, char* outname, ch
 	      }
 	    }
 	  }
-	  new_row++;
 	}
 	row++;
 	progress += row;
@@ -6700,7 +6697,7 @@ int32_t calc_rel(pthread_t* threads, uint32_t parallel_idx, uint32_t parallel_to
       }
       strcpy(outname_end, ".rel.bin");
       if (parallel_tot > 1) {
-	sprintf(&(outname_end[8]), ".%u", parallel_idx + 1);
+	snprintf(&(outname_end[8]), MAX_POST_EXT - 8, ".%u", parallel_idx + 1);
       }
       if (fopen_checked(outname, FOPEN_WB, &outfile)) {
 	goto calc_rel_ret_OPEN_FAIL;
@@ -6793,7 +6790,7 @@ int32_t calc_rel(pthread_t* threads, uint32_t parallel_idx, uint32_t parallel_to
       // make this .rel.bin4?
       strcpy(outname_end, ".rel.bin");
       if (parallel_tot > 1) {
-	sprintf(&(outname_end[8]), ".%u", parallel_idx + 1);
+	snprintf(&(outname_end[8]), MAX_POST_EXT - 8, ".%u", parallel_idx + 1);
       }
       if (fopen_checked(outname, FOPEN_WB, &outfile)) {
 	goto calc_rel_ret_OPEN_FAIL;
@@ -6857,7 +6854,7 @@ int32_t calc_rel(pthread_t* threads, uint32_t parallel_idx, uint32_t parallel_to
 	} else {
 	  strcpy(outname_end, ".grm");
 	  if (parallel_tot > 1) {
-	    sprintf(&(outname_end[4]), ".%u", parallel_idx + 1);
+	    snprintf(&(outname_end[4]), MAX_POST_EXT - 4, ".%u", parallel_idx + 1);
 	  }
 	  retval = write_uncompressed(outname, overflow_buf, 0, calc_rel_grm_emitn);
 	  if (retval) {
@@ -6874,7 +6871,7 @@ int32_t calc_rel(pthread_t* threads, uint32_t parallel_idx, uint32_t parallel_to
 	} else {
 	  strcpy(outname_end, ".rel");
 	  if (parallel_tot > 1) {
-	    sprintf(&(outname_end[4]), ".%u", parallel_idx + 1);
+	    snprintf(&(outname_end[4]), MAX_POST_EXT - 4, ".%u", parallel_idx + 1);
 	  }
 	}
 	if (rel_shape == REL_CALC_TRI) {
@@ -6938,7 +6935,7 @@ int32_t calc_rel(pthread_t* threads, uint32_t parallel_idx, uint32_t parallel_to
       if (retval) {
 	goto calc_rel_ret_1;
       }
-      sprintf(wptr, " , and IDs written to %s .\n", outname);
+      snprintf(wptr, LOGBUFLEN - (wptr - g_logbuf), " , and IDs written to %s .\n", outname);
     } else {
       snprintf(g_logbuf, LOGBUFLEN, "Relationship matrix component written to %s .\n", outname);
     }
@@ -8066,7 +8063,7 @@ int32_t calc_distance(pthread_t* threads, uint32_t parallel_idx, uint32_t parall
       if (retval) {
 	goto calc_distance_ret_1;
       }
-      sprintf(wptr, " , and IDs to %s .\n", outname);
+      snprintf(wptr, LOGBUFLEN - (wptr - g_logbuf), " , and IDs to %s .\n", outname);
     } else {
       snprintf(g_logbuf, LOGBUFLEN, "Distances (proportions) written to %s .\n", outname);
     }
diff --git a/1.9/plink_common.h b/1.9/plink_common.h
index 29f0e68e..6a03b822 100644
--- a/1.9/plink_common.h
+++ b/1.9/plink_common.h
@@ -265,7 +265,7 @@
     #error "zlib version 1.2.4 or later required."
   #endif
 #else
-  #include "../zlib-1.2.13/zlib.h"
+  #include "../zlib-1.3/zlib.h"
 #endif
 #include "SFMT.h"
 
diff --git a/1.9/plink_first_compile b/1.9/plink_first_compile
index 0a4e8332..cfedf0df 100755
--- a/1.9/plink_first_compile
+++ b/1.9/plink_first_compile
@@ -2,24 +2,24 @@
 
 # Download zlib into parent directory, and verify
 cd ..
-curl -Of http://zlib.net/zlib-1.2.13.tar.gz
+curl -Of http://zlib.net/zlib-1.3.tar.gz
 last_exit_code=$?
 if [ $last_exit_code -ne 0 ]; then
     # There's a newer zlib, and we might want to update this script.  But
     # download the hardcoded version for now to make the static build work...
-    curl -O http://zlib.net/fossils/zlib-1.2.13.tar.gz
+    curl -O http://zlib.net/fossils/zlib-1.3.tar.gz
 fi
 
-EXPECTEDCHECKSUM=55eaa84906f31ac20d725aa26cd20839196b6ba6
-CHECKSUM=$(shasum zlib-1.2.13.tar.gz | cut -b-40)
+EXPECTEDCHECKSUM=04d053e4d4064a0fb8f0cbd127f0bfb5fe4eb554
+CHECKSUM=$(shasum zlib-1.3.tar.gz | cut -b-40)
 if [ "$EXPECTEDCHECKSUM" != "$CHECKSUM" ]; then
     echo "Zlib checksum verification failure"
     exit 1
 fi;
 
 # Unpack and compile zlib
-tar -xzvf zlib-1.2.13.tar.gz
-cd zlib-1.2.13
+tar -xzvf zlib-1.3.tar.gz
+cd zlib-1.3
 ./configure
 make
 
diff --git a/1.9/plink_lasso.c b/1.9/plink_lasso.c
index 8104bd77..2a3ffd8a 100644
--- a/1.9/plink_lasso.c
+++ b/1.9/plink_lasso.c
@@ -32,7 +32,6 @@ int32_t transpose_covar(const uintptr_t* sample_exclude, const uintptr_t* pheno_
   double ssq = 0.0;
   double* writeptr = writeptr_start;
   uint32_t sample_uidx = 0;
-  uint32_t uii = 0;
   for (uint32_t sample_idx = 0; sample_idx < sample_ct; ++sample_uidx, ++sample_idx) {
     next_unset_unsafe_ck(sample_exclude, &sample_uidx);
     if (IS_SET(pheno_nm, sample_uidx)) {
@@ -40,7 +39,6 @@ int32_t transpose_covar(const uintptr_t* sample_exclude, const uintptr_t* pheno_
       sum += dxx;
       ssq += dxx * dxx;
       *writeptr++ = dxx;
-      ++uii;
     }
   }
   if (ssq * ((double)sample_valid_ct) == sum * sum) {
diff --git a/2.0/Makefile.src b/2.0/Makefile.src
index 4c395959..ffd22523 100644
--- a/2.0/Makefile.src
+++ b/2.0/Makefile.src
@@ -91,7 +91,7 @@ CCSRC = $(PLINK2LIB_CCSRC) \
         plink2_random.cc \
         plink2_set.cc
 
-ZLIB_VER = 1.2.13
+ZLIB_VER = 1.3
 
 OBJ_NO_ZSTD = $(CSRC:.c=.o) $(CCSRC:.cc=.o)
 OBJ = $(CSRC:.c=.o) $(ZCSRC:.c=.o) $(ZSSRC:.S=.o) $(CCSRC:.cc=.o)
diff --git a/2.0/include/plink2_text.h b/2.0/include/plink2_text.h
index 594a13b1..3c88285a 100644
--- a/2.0/include/plink2_text.h
+++ b/2.0/include/plink2_text.h
@@ -100,7 +100,7 @@
 // - A simpler single-threaded (no decompress-ahead) reader.
 
 #ifdef STATIC_ZLIB
-#  include "../../zlib-1.2.13/zlib.h"
+#  include "../../zlib-1.3/zlib.h"
 #else
 #  include <zlib.h>
 #  if !defined(ZLIB_VERNUM) || (ZLIB_VERNUM < 0x1240)