diff --git a/include/zlib/ChangeLog b/include/zlib/ChangeLog
index 8707988ac1..b801a1031e 100644
--- a/include/zlib/ChangeLog
+++ b/include/zlib/ChangeLog
@@ -1,6 +1,16 @@
 
                 ChangeLog file for zlib
 
+Changes in 1.3.1 (22 Jan 2024)
+- Reject overflows of zip header fields in minizip
+- Fix bug in inflateSync() for data held in bit buffer
+- Add LIT_MEM define to use more memory for a small deflate speedup
+- Fix decision on the emission of Zip64 end records in minizip
+- Add bounds checking to ERR_MSG() macro, used by zError()
+- Neutralize zip file traversal attacks in miniunz
+- Fix a bug in ZLIB_DEBUG compiles in check_match()
+- Various portability and appearance improvements
+
 Changes in 1.3 (18 Aug 2023)
 - Remove K&R function definitions and zlib2ansi
 - Fix bug in deflateBound() for level 0 and memLevel 9
diff --git a/include/zlib/FAQ b/include/zlib/FAQ
index 55f1cdc22f..92f5d3e29f 100644
--- a/include/zlib/FAQ
+++ b/include/zlib/FAQ
@@ -14,8 +14,7 @@ The latest zlib FAQ is at http://zlib.net/zlib_faq.html
  2. Where can I get a Windows DLL version?
 
     The zlib sources can be compiled without change to produce a DLL.  See the
-    file win32/DLL_FAQ.txt in the zlib distribution.  Pointers to the
-    precompiled DLL are found in the zlib web site at http://zlib.net/ .
+    file win32/DLL_FAQ.txt in the zlib distribution.
 
  3. Where can I get a Visual Basic interface to zlib?
 
diff --git a/include/zlib/OpenMPT.txt b/include/zlib/OpenMPT.txt
index eb5fb43cc2..eebbe62026 100644
--- a/include/zlib/OpenMPT.txt
+++ b/include/zlib/OpenMPT.txt
@@ -1,4 +1,4 @@
-zlib 1.3.
+zlib 1.3.1.
 Files not required by OpenMPT have been removed.
 OpenMPT specific changes:
  *  iowin32.c has been modified to only use Windows 8 WinRT API when actually
diff --git a/include/zlib/README b/include/zlib/README
index e02fc5aa20..c5f917540b 100644
--- a/include/zlib/README
+++ b/include/zlib/README
@@ -1,6 +1,6 @@
 ZLIB DATA COMPRESSION LIBRARY
 
-zlib 1.3 is a general purpose data compression library.  All the code is
+zlib 1.3.1 is a general purpose data compression library.  All the code is
 thread safe.  The data format used by the zlib library is described by RFCs
 (Request for Comments) 1950 to 1952 in the files
 http://tools.ietf.org/html/rfc1950 (zlib format), rfc1951 (deflate format) and
@@ -31,7 +31,7 @@ Mark Nelson <markn@ieee.org> wrote an article about zlib for the Jan.  1997
 issue of Dr.  Dobb's Journal; a copy of the article is available at
 https://marknelson.us/posts/1997/01/01/zlib-engine.html .
 
-The changes made in version 1.3 are documented in the file ChangeLog.
+The changes made in version 1.3.1 are documented in the file ChangeLog.
 
 Unsupported third party contributions are provided in directory contrib/ .
 
@@ -83,7 +83,7 @@ Acknowledgments:
 
 Copyright notice:
 
- (C) 1995-2023 Jean-loup Gailly and Mark Adler
+ (C) 1995-2024 Jean-loup Gailly and Mark Adler
 
   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
diff --git a/include/zlib/contrib/minizip/ioapi.h b/include/zlib/contrib/minizip/ioapi.h
index c588a18d03..a2d2e6e60d 100644
--- a/include/zlib/contrib/minizip/ioapi.h
+++ b/include/zlib/contrib/minizip/ioapi.h
@@ -144,7 +144,7 @@ typedef long     (ZCALLBACK *tell_file_func)      (voidpf opaque, voidpf stream)
 typedef long     (ZCALLBACK *seek_file_func)      (voidpf opaque, voidpf stream, uLong offset, int origin);
 
 
-/* here is the "old" 32 bits structure structure */
+/* here is the "old" 32 bits structure */
 typedef struct zlib_filefunc_def_s
 {
     open_file_func      zopen_file;
diff --git a/include/zlib/contrib/minizip/miniunz.c b/include/zlib/contrib/minizip/miniunz.c
index a12aec8bea..d627c4226b 100644
--- a/include/zlib/contrib/minizip/miniunz.c
+++ b/include/zlib/contrib/minizip/miniunz.c
@@ -79,7 +79,7 @@
 
 /* change_file_date : change the date/time of a file
     filename : the filename of the file where date/time must be modified
-    dosdate : the new date at the MSDos format (4 bytes)
+    dosdate : the new date at the MSDOS format (4 bytes)
     tmu_date : the SAME new date at the tm_unz format */
 static void change_file_date(const char *filename, uLong dosdate, tm_unz tmu_date) {
 #ifdef _WIN32
@@ -186,7 +186,7 @@ static int makedir(const char *newdir) {
 }
 
 static void do_banner(void) {
-    printf("MiniUnz 1.01b, demo of zLib + Unz package written by Gilles Vollant\n");
+    printf("MiniUnz 1.1, demo of zLib + Unz package written by Gilles Vollant\n");
     printf("more info at http://www.winimage.com/zLibDll/unzip.html\n\n");
 }
 
@@ -356,6 +356,20 @@ static int do_extract_currentfile(unzFile uf, const int* popt_extract_without_pa
         else
             write_filename = filename_withoutpath;
 
+        if (write_filename[0]!='\0')
+        {
+            const char* relative_check = write_filename;
+            while (relative_check[1]!='\0')
+            {
+                if (relative_check[0]=='.' && relative_check[1]=='.')
+                    write_filename = relative_check;
+                relative_check++;
+            }
+        }
+
+        while (write_filename[0]=='/' || write_filename[0]=='.')
+            write_filename++;
+
         err = unzOpenCurrentFilePassword(uf,password);
         if (err!=UNZ_OK)
         {
diff --git a/include/zlib/contrib/minizip/unzip.c b/include/zlib/contrib/minizip/unzip.c
index ed763f89f1..ea05b7d62a 100644
--- a/include/zlib/contrib/minizip/unzip.c
+++ b/include/zlib/contrib/minizip/unzip.c
@@ -117,7 +117,7 @@
 const char unz_copyright[] =
    " unzip 1.01 Copyright 1998-2004 Gilles Vollant - http://www.winimage.com/zLibDll";
 
-/* unz_file_info_interntal contain internal info about a file in zipfile*/
+/* unz_file_info64_internal contain internal info about a file in zipfile*/
 typedef struct unz_file_info64_internal_s
 {
     ZPOS64_T offset_curfile;/* relative offset of local header 8 bytes */
@@ -450,7 +450,7 @@ local ZPOS64_T unz64local_SearchCentralDir64(const zlib_filefunc64_32_def* pzlib
     if (unz64local_getLong(pzlib_filefunc_def,filestream,&uL)!=UNZ_OK)
         return CENTRALDIRINVALID;
 
-    /* number of the disk with the start of the zip64 end of  central directory */
+    /* number of the disk with the start of the zip64 end of central directory */
     if (unz64local_getLong(pzlib_filefunc_def,filestream,&uL)!=UNZ_OK)
         return CENTRALDIRINVALID;
     if (uL != 0)
@@ -497,9 +497,9 @@ local unzFile unzOpenInternal(const void *path,
     ZPOS64_T central_pos;
     uLong   uL;
 
-    uLong number_disk;          /* number of the current dist, used for
+    uLong number_disk;          /* number of the current disk, used for
                                    spanning ZIP, unsupported, always 0*/
-    uLong number_disk_with_CD;  /* number the the disk with central dir, used
+    uLong number_disk_with_CD;  /* number the disk with central dir, used
                                    for spanning ZIP, unsupported, always 0*/
     ZPOS64_T number_entry_CD;      /* total number of entries in
                                    the central dir
diff --git a/include/zlib/contrib/minizip/unzip.h b/include/zlib/contrib/minizip/unzip.h
index 14105840f6..5cfc9c6274 100644
--- a/include/zlib/contrib/minizip/unzip.h
+++ b/include/zlib/contrib/minizip/unzip.h
@@ -306,7 +306,7 @@ extern int ZEXPORT unzGetCurrentFileInfo(unzFile file,
   Get Info about the current file
   if pfile_info!=NULL, the *pfile_info structure will contain some info about
         the current file
-  if szFileName!=NULL, the filemane string will be copied in szFileName
+  if szFileName!=NULL, the filename string will be copied in szFileName
             (fileNameBufferSize is the size of the buffer)
   if extraField!=NULL, the extra field information will be copied in extraField
             (extraFieldBufferSize is the size of the buffer).
diff --git a/include/zlib/contrib/minizip/zip.c b/include/zlib/contrib/minizip/zip.c
index 8b400332aa..b259194326 100644
--- a/include/zlib/contrib/minizip/zip.c
+++ b/include/zlib/contrib/minizip/zip.c
@@ -575,7 +575,7 @@ local ZPOS64_T zip64local_SearchCentralDir64(const zlib_filefunc64_32_def* pzlib
   if (zip64local_getLong(pzlib_filefunc_def,filestream,&uL)!=ZIP_OK)
     return 0;
 
-  /* number of the disk with the start of the zip64 end of  central directory */
+  /* number of the disk with the start of the zip64 end of central directory */
   if (zip64local_getLong(pzlib_filefunc_def,filestream,&uL)!=ZIP_OK)
     return 0;
   if (uL != 0)
@@ -614,9 +614,9 @@ local int LoadCentralDirectoryRecord(zip64_internal* pziinit) {
   ZPOS64_T central_pos;
   uLong uL;
 
-  uLong number_disk;          /* number of the current dist, used for
+  uLong number_disk;          /* number of the current disk, used for
                               spanning ZIP, unsupported, always 0*/
-  uLong number_disk_with_CD;  /* number the the disk with central dir, used
+  uLong number_disk_with_CD;  /* number of the disk with central dir, used
                               for spanning ZIP, unsupported, always 0*/
   ZPOS64_T number_entry;
   ZPOS64_T number_entry_CD;      /* total number of entries in
@@ -1043,6 +1043,17 @@ extern int ZEXPORT zipOpenNewFileInZip4_64(zipFile file, const char* filename, c
       return ZIP_PARAMERROR;
 #endif
 
+    // The filename and comment length must fit in 16 bits.
+    if ((filename!=NULL) && (strlen(filename)>0xffff))
+        return ZIP_PARAMERROR;
+    if ((comment!=NULL) && (strlen(comment)>0xffff))
+        return ZIP_PARAMERROR;
+    // The extra field length must fit in 16 bits. If the member also requires
+    // a Zip64 extra block, that will also need to fit within that 16-bit
+    // length, but that will be checked for later.
+    if ((size_extrafield_local>0xffff) || (size_extrafield_global>0xffff))
+        return ZIP_PARAMERROR;
+
     zi = (zip64_internal*)file;
 
     if (zi->in_opened_file_inzip == 1)
@@ -1597,7 +1608,7 @@ extern int ZEXPORT zipCloseFileInZipRaw64(zipFile file, ZPOS64_T uncompressed_si
 
       if((uLong)(datasize + 4) > zi->ci.size_centralExtraFree)
       {
-        // we can not write more data to the buffer that we have room for.
+        // we cannot write more data to the buffer that we have room for.
         return ZIP_BADZIPFILE;
       }
 
@@ -1861,7 +1872,7 @@ extern int ZEXPORT zipClose(zipFile file, const char* global_comment) {
     free_linkedlist(&(zi->central_dir));
 
     pos = centraldir_pos_inzip - zi->add_position_when_writing_offset;
-    if(pos >= 0xffffffff || zi->number_entry > 0xFFFF)
+    if(pos >= 0xffffffff || zi->number_entry >= 0xFFFF)
     {
       ZPOS64_T Zip64EOCDpos = ZTELL64(zi->z_filefunc,zi->filestream);
       Write_Zip64EndOfCentralDirectoryRecord(zi, size_centraldir, centraldir_pos_inzip);
diff --git a/include/zlib/contrib/minizip/zip.h b/include/zlib/contrib/minizip/zip.h
index 5fc0841324..3e230d3405 100644
--- a/include/zlib/contrib/minizip/zip.h
+++ b/include/zlib/contrib/minizip/zip.h
@@ -177,9 +177,9 @@ extern int ZEXPORT zipOpenNewFileInZip64(zipFile file,
   filename : the filename in zip (if NULL, '-' without quote will be used
   *zipfi contain supplemental information
   if extrafield_local!=NULL and size_extrafield_local>0, extrafield_local
-    contains the extrafield data the the local header
+    contains the extrafield data for the local header
   if extrafield_global!=NULL and size_extrafield_global>0, extrafield_global
-    contains the extrafield data the the local header
+    contains the extrafield data for the global header
   if comment != NULL, comment contain the comment string
   method contain the compression method (0 for store, Z_DEFLATED for deflate)
   level contain the level of compression (can be Z_DEFAULT_COMPRESSION)
diff --git a/include/zlib/deflate.c b/include/zlib/deflate.c
index bd01175192..012ea8148e 100644
--- a/include/zlib/deflate.c
+++ b/include/zlib/deflate.c
@@ -1,5 +1,5 @@
 /* deflate.c -- compress data using the deflation algorithm
- * Copyright (C) 1995-2023 Jean-loup Gailly and Mark Adler
+ * Copyright (C) 1995-2024 Jean-loup Gailly and Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -52,7 +52,7 @@
 #include "deflate.h"
 
 const char deflate_copyright[] =
-   " deflate 1.3 Copyright 1995-2023 Jean-loup Gailly and Mark Adler ";
+   " deflate 1.3.1 Copyright 1995-2024 Jean-loup Gailly and Mark Adler ";
 /*
   If you use the zlib library in a product, an acknowledgment is welcome
   in the documentation of your product. If for some reason you cannot
@@ -493,7 +493,7 @@ int ZEXPORT deflateInit2_(z_streamp strm, int level, int method,
      * symbols from which it is being constructed.
      */
 
-    s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, 4);
+    s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, LIT_BUFS);
     s->pending_buf_size = (ulg)s->lit_bufsize * 4;
 
     if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
@@ -503,8 +503,14 @@ int ZEXPORT deflateInit2_(z_streamp strm, int level, int method,
         deflateEnd (strm);
         return Z_MEM_ERROR;
     }
+#ifdef LIT_MEM
+    s->d_buf = (ushf *)(s->pending_buf + (s->lit_bufsize << 1));
+    s->l_buf = s->pending_buf + (s->lit_bufsize << 2);
+    s->sym_end = s->lit_bufsize - 1;
+#else
     s->sym_buf = s->pending_buf + s->lit_bufsize;
     s->sym_end = (s->lit_bufsize - 1) * 3;
+#endif
     /* We avoid equality with lit_bufsize*3 because of wraparound at 64K
      * on 16 bit machines and because stored blocks are restricted to
      * 64K-1 bytes.
@@ -720,9 +726,15 @@ int ZEXPORT deflatePrime(z_streamp strm, int bits, int value) {
 
     if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
     s = strm->state;
+#ifdef LIT_MEM
+    if (bits < 0 || bits > 16 ||
+        (uchf *)s->d_buf < s->pending_out + ((Buf_size + 7) >> 3))
+        return Z_BUF_ERROR;
+#else
     if (bits < 0 || bits > 16 ||
         s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3))
         return Z_BUF_ERROR;
+#endif
     do {
         put = Buf_size - s->bi_valid;
         if (put > bits)
@@ -1294,7 +1306,7 @@ int ZEXPORT deflateCopy(z_streamp dest, z_streamp source) {
     ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
     ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
     ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
-    ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4);
+    ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, LIT_BUFS);
 
     if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
         ds->pending_buf == Z_NULL) {
@@ -1305,10 +1317,15 @@ int ZEXPORT deflateCopy(z_streamp dest, z_streamp source) {
     zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
     zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
     zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));
-    zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
+    zmemcpy(ds->pending_buf, ss->pending_buf, ds->lit_bufsize * LIT_BUFS);
 
     ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
+#ifdef LIT_MEM
+    ds->d_buf = (ushf *)(ds->pending_buf + (ds->lit_bufsize << 1));
+    ds->l_buf = ds->pending_buf + (ds->lit_bufsize << 2);
+#else
     ds->sym_buf = ds->pending_buf + ds->lit_bufsize;
+#endif
 
     ds->l_desc.dyn_tree = ds->dyn_ltree;
     ds->d_desc.dyn_tree = ds->dyn_dtree;
@@ -1539,13 +1556,21 @@ local uInt longest_match(deflate_state *s, IPos cur_match) {
  */
 local void check_match(deflate_state *s, IPos start, IPos match, int length) {
     /* check that the match is indeed a match */
-    if (zmemcmp(s->window + match,
-                s->window + start, length) != EQUAL) {
-        fprintf(stderr, " start %u, match %u, length %d\n",
-                start, match, length);
+    Bytef *back = s->window + (int)match, *here = s->window + start;
+    IPos len = length;
+    if (match == (IPos)-1) {
+        /* match starts one byte before the current window -- just compare the
+           subsequent length-1 bytes */
+        back++;
+        here++;
+        len--;
+    }
+    if (zmemcmp(back, here, len) != EQUAL) {
+        fprintf(stderr, " start %u, match %d, length %d\n",
+                start, (int)match, length);
         do {
-            fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
-        } while (--length != 0);
+            fprintf(stderr, "(%02x %02x)", *back++, *here++);
+        } while (--len != 0);
         z_error("invalid match");
     }
     if (z_verbose > 1) {
diff --git a/include/zlib/deflate.h b/include/zlib/deflate.h
index 8696791429..300c6ada62 100644
--- a/include/zlib/deflate.h
+++ b/include/zlib/deflate.h
@@ -1,5 +1,5 @@
 /* deflate.h -- internal compression state
- * Copyright (C) 1995-2018 Jean-loup Gailly
+ * Copyright (C) 1995-2024 Jean-loup Gailly
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -23,6 +23,10 @@
 #  define GZIP
 #endif
 
+/* define LIT_MEM to slightly increase the speed of deflate (order 1% to 2%) at
+   the cost of a larger memory footprint */
+/* #define LIT_MEM */
+
 /* ===========================================================================
  * Internal compression state.
  */
@@ -217,7 +221,14 @@ typedef struct internal_state {
     /* Depth of each subtree used as tie breaker for trees of equal frequency
      */
 
+#ifdef LIT_MEM
+#   define LIT_BUFS 5
+    ushf *d_buf;          /* buffer for distances */
+    uchf *l_buf;          /* buffer for literals/lengths */
+#else
+#   define LIT_BUFS 4
     uchf *sym_buf;        /* buffer for distances and literals/lengths */
+#endif
 
     uInt  lit_bufsize;
     /* Size of match buffer for literals/lengths.  There are 4 reasons for
@@ -239,7 +250,7 @@ typedef struct internal_state {
      *   - I can't count above 4
      */
 
-    uInt sym_next;      /* running index in sym_buf */
+    uInt sym_next;      /* running index in symbol buffer */
     uInt sym_end;       /* symbol table full when sym_next reaches this */
 
     ulg opt_len;        /* bit length of current block with optimal trees */
@@ -318,6 +329,25 @@ void ZLIB_INTERNAL _tr_stored_block(deflate_state *s, charf *buf,
   extern const uch ZLIB_INTERNAL _dist_code[];
 #endif
 
+#ifdef LIT_MEM
+# define _tr_tally_lit(s, c, flush) \
+  { uch cc = (c); \
+    s->d_buf[s->sym_next] = 0; \
+    s->l_buf[s->sym_next++] = cc; \
+    s->dyn_ltree[cc].Freq++; \
+    flush = (s->sym_next == s->sym_end); \
+   }
+# define _tr_tally_dist(s, distance, length, flush) \
+  { uch len = (uch)(length); \
+    ush dist = (ush)(distance); \
+    s->d_buf[s->sym_next] = dist; \
+    s->l_buf[s->sym_next++] = len; \
+    dist--; \
+    s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
+    s->dyn_dtree[d_code(dist)].Freq++; \
+    flush = (s->sym_next == s->sym_end); \
+  }
+#else
 # define _tr_tally_lit(s, c, flush) \
   { uch cc = (c); \
     s->sym_buf[s->sym_next++] = 0; \
@@ -337,6 +367,7 @@ void ZLIB_INTERNAL _tr_stored_block(deflate_state *s, charf *buf,
     s->dyn_dtree[d_code(dist)].Freq++; \
     flush = (s->sym_next == s->sym_end); \
   }
+#endif
 #else
 # define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c)
 # define _tr_tally_dist(s, distance, length, flush) \
diff --git a/include/zlib/gzguts.h b/include/zlib/gzguts.h
index f9375047e8..eba72085bb 100644
--- a/include/zlib/gzguts.h
+++ b/include/zlib/gzguts.h
@@ -1,5 +1,5 @@
 /* gzguts.h -- zlib internal header definitions for gz* operations
- * Copyright (C) 2004-2019 Mark Adler
+ * Copyright (C) 2004-2024 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -210,9 +210,5 @@ char ZLIB_INTERNAL *gz_strwinerror(DWORD error);
 /* GT_OFF(x), where x is an unsigned value, is true if x > maximum z_off64_t
    value -- needed when comparing unsigned to z_off64_t, which is signed
    (possible z_off64_t types off_t, off64_t, and long are all signed) */
-#ifdef INT_MAX
-#  define GT_OFF(x) (sizeof(int) == sizeof(z_off64_t) && (x) > INT_MAX)
-#else
 unsigned ZLIB_INTERNAL gz_intmax(void);
-#  define GT_OFF(x) (sizeof(int) == sizeof(z_off64_t) && (x) > gz_intmax())
-#endif
+#define GT_OFF(x) (sizeof(int) == sizeof(z_off64_t) && (x) > gz_intmax())
diff --git a/include/zlib/gzlib.c b/include/zlib/gzlib.c
index 29fc4486fb..983153cc8e 100644
--- a/include/zlib/gzlib.c
+++ b/include/zlib/gzlib.c
@@ -1,5 +1,5 @@
 /* gzlib.c -- zlib functions common to reading and writing gzip files
- * Copyright (C) 2004-2019 Mark Adler
+ * Copyright (C) 2004-2024 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -563,20 +563,20 @@ void ZLIB_INTERNAL gz_error(gz_statep state, int err, const char *msg) {
 #endif
 }
 
-#ifndef INT_MAX
 /* portably return maximum value for an int (when limits.h presumed not
    available) -- we need to do this to cover cases where 2's complement not
    used, since C standard permits 1's complement and sign-bit representations,
    otherwise we could just use ((unsigned)-1) >> 1 */
 unsigned ZLIB_INTERNAL gz_intmax(void) {
-    unsigned p, q;
-
-    p = 1;
+#ifdef INT_MAX
+    return INT_MAX;
+#else
+    unsigned p = 1, q;
     do {
         q = p;
         p <<= 1;
         p++;
     } while (p > q);
     return q >> 1;
-}
 #endif
+}
diff --git a/include/zlib/inflate.c b/include/zlib/inflate.c
index b0757a9b24..94ecff015a 100644
--- a/include/zlib/inflate.c
+++ b/include/zlib/inflate.c
@@ -1387,7 +1387,7 @@ int ZEXPORT inflateSync(z_streamp strm) {
     /* if first time, start search in bit buffer */
     if (state->mode != SYNC) {
         state->mode = SYNC;
-        state->hold <<= state->bits & 7;
+        state->hold >>= state->bits & 7;
         state->bits -= state->bits & 7;
         len = 0;
         while (state->bits >= 8) {
diff --git a/include/zlib/inftrees.c b/include/zlib/inftrees.c
index 8a208c2daa..98cfe16445 100644
--- a/include/zlib/inftrees.c
+++ b/include/zlib/inftrees.c
@@ -1,5 +1,5 @@
 /* inftrees.c -- generate Huffman trees for efficient decoding
- * Copyright (C) 1995-2023 Mark Adler
+ * Copyright (C) 1995-2024 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -9,7 +9,7 @@
 #define MAXBITS 15
 
 const char inflate_copyright[] =
-   " inflate 1.3 Copyright 1995-2023 Mark Adler ";
+   " inflate 1.3.1 Copyright 1995-2024 Mark Adler ";
 /*
   If you use the zlib library in a product, an acknowledgment is welcome
   in the documentation of your product. If for some reason you cannot
@@ -57,7 +57,7 @@ int ZLIB_INTERNAL inflate_table(codetype type, unsigned short FAR *lens,
         35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
     static const unsigned short lext[31] = { /* Length codes 257..285 extra */
         16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18,
-        19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 198, 203};
+        19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 203, 77};
     static const unsigned short dbase[32] = { /* Distance codes 0..29 base */
         1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
         257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
diff --git a/include/zlib/inftrees.h b/include/zlib/inftrees.h
index a10712d8cb..396f74b5da 100644
--- a/include/zlib/inftrees.h
+++ b/include/zlib/inftrees.h
@@ -41,8 +41,8 @@ typedef struct {
    examples/enough.c found in the zlib distribution.  The arguments to that
    program are the number of symbols, the initial root table size, and the
    maximum bit length of a code.  "enough 286 9 15" for literal/length codes
-   returns returns 852, and "enough 30 6 15" for distance codes returns 592.
-   The initial root table size (9 or 6) is found in the fifth argument of the
+   returns 852, and "enough 30 6 15" for distance codes returns 592. The
+   initial root table size (9 or 6) is found in the fifth argument of the
    inflate_table() calls in inflate.c and infback.c.  If the root table size is
    changed, then these maximum sizes would be need to be recalculated and
    updated. */
diff --git a/include/zlib/trees.c b/include/zlib/trees.c
index 8dbdc40bac..6a523ef34e 100644
--- a/include/zlib/trees.c
+++ b/include/zlib/trees.c
@@ -1,5 +1,5 @@
 /* trees.c -- output deflated data using Huffman coding
- * Copyright (C) 1995-2021 Jean-loup Gailly
+ * Copyright (C) 1995-2024 Jean-loup Gailly
  * detect_data_type() function provided freely by Cosmin Truta, 2006
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
@@ -899,14 +899,19 @@ local void compress_block(deflate_state *s, const ct_data *ltree,
                           const ct_data *dtree) {
     unsigned dist;      /* distance of matched string */
     int lc;             /* match length or unmatched char (if dist == 0) */
-    unsigned sx = 0;    /* running index in sym_buf */
+    unsigned sx = 0;    /* running index in symbol buffers */
     unsigned code;      /* the code to send */
     int extra;          /* number of extra bits to send */
 
     if (s->sym_next != 0) do {
+#ifdef LIT_MEM
+        dist = s->d_buf[sx];
+        lc = s->l_buf[sx++];
+#else
         dist = s->sym_buf[sx++] & 0xff;
         dist += (unsigned)(s->sym_buf[sx++] & 0xff) << 8;
         lc = s->sym_buf[sx++];
+#endif
         if (dist == 0) {
             send_code(s, lc, ltree); /* send a literal byte */
             Tracecv(isgraph(lc), (stderr," '%c' ", lc));
@@ -931,8 +936,12 @@ local void compress_block(deflate_state *s, const ct_data *ltree,
             }
         } /* literal or match pair ? */
 
-        /* Check that the overlay between pending_buf and sym_buf is ok: */
+        /* Check for no overlay of pending_buf on needed symbols */
+#ifdef LIT_MEM
+        Assert(s->pending < 2 * (s->lit_bufsize + sx), "pendingBuf overflow");
+#else
         Assert(s->pending < s->lit_bufsize + sx, "pendingBuf overflow");
+#endif
 
     } while (sx < s->sym_next);
 
@@ -1082,9 +1091,14 @@ void ZLIB_INTERNAL _tr_flush_block(deflate_state *s, charf *buf,
  * the current block must be flushed.
  */
 int ZLIB_INTERNAL _tr_tally(deflate_state *s, unsigned dist, unsigned lc) {
+#ifdef LIT_MEM
+    s->d_buf[s->sym_next] = (ush)dist;
+    s->l_buf[s->sym_next++] = (uch)lc;
+#else
     s->sym_buf[s->sym_next++] = (uch)dist;
     s->sym_buf[s->sym_next++] = (uch)(dist >> 8);
     s->sym_buf[s->sym_next++] = (uch)lc;
+#endif
     if (dist == 0) {
         /* lc is the unmatched char */
         s->dyn_ltree[lc].Freq++;
diff --git a/include/zlib/zconf.h b/include/zlib/zconf.h
index fb76ffe312..62adc8d843 100644
--- a/include/zlib/zconf.h
+++ b/include/zlib/zconf.h
@@ -1,5 +1,5 @@
 /* zconf.h -- configuration of the zlib compression library
- * Copyright (C) 1995-2016 Jean-loup Gailly, Mark Adler
+ * Copyright (C) 1995-2024 Jean-loup Gailly, Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -300,14 +300,6 @@
 #  endif
 #endif
 
-#ifndef Z_ARG /* function prototypes for stdarg */
-#  if defined(STDC) || defined(Z_HAVE_STDARG_H)
-#    define Z_ARG(args)  args
-#  else
-#    define Z_ARG(args)  ()
-#  endif
-#endif
-
 /* The following definitions for FAR are needed only for MSDOS mixed
  * model programming (small or medium model with some far allocations).
  * This was tested only with MSC; for other MSDOS compilers you may have
diff --git a/include/zlib/zlib.h b/include/zlib/zlib.h
index 6b7244f994..8d4b932eaf 100644
--- a/include/zlib/zlib.h
+++ b/include/zlib/zlib.h
@@ -1,7 +1,7 @@
 /* zlib.h -- interface of the 'zlib' general purpose compression library
-  version 1.3, August 18th, 2023
+  version 1.3.1, January 22nd, 2024
 
-  Copyright (C) 1995-2023 Jean-loup Gailly and Mark Adler
+  Copyright (C) 1995-2024 Jean-loup Gailly and Mark Adler
 
   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
@@ -37,11 +37,11 @@
 extern "C" {
 #endif
 
-#define ZLIB_VERSION "1.3"
-#define ZLIB_VERNUM 0x1300
+#define ZLIB_VERSION "1.3.1"
+#define ZLIB_VERNUM 0x1310
 #define ZLIB_VER_MAJOR 1
 #define ZLIB_VER_MINOR 3
-#define ZLIB_VER_REVISION 0
+#define ZLIB_VER_REVISION 1
 #define ZLIB_VER_SUBREVISION 0
 
 /*
@@ -936,10 +936,10 @@ ZEXTERN int ZEXPORT inflateSync(z_streamp strm);
      inflateSync returns Z_OK if a possible full flush point has been found,
    Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
    has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
-   In the success case, the application may save the current current value of
-   total_in which indicates where valid compressed data was found.  In the
-   error case, the application may repeatedly call inflateSync, providing more
-   input each time, until success or end of the input data.
+   In the success case, the application may save the current value of total_in
+   which indicates where valid compressed data was found.  In the error case,
+   the application may repeatedly call inflateSync, providing more input each
+   time, until success or end of the input data.
 */
 
 ZEXTERN int ZEXPORT inflateCopy(z_streamp dest,
@@ -1758,14 +1758,14 @@ ZEXTERN uLong ZEXPORT crc32_combine(uLong crc1, uLong crc2, z_off_t len2);
    seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
    calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
    check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
-   len2.
+   len2. len2 must be non-negative.
 */
 
 /*
 ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t len2);
 
      Return the operator corresponding to length len2, to be used with
-   crc32_combine_op().
+   crc32_combine_op(). len2 must be non-negative.
 */
 
 ZEXTERN uLong ZEXPORT crc32_combine_op(uLong crc1, uLong crc2, uLong op);
diff --git a/include/zlib/zutil.h b/include/zlib/zutil.h
index 902a304cc2..48dd7febae 100644
--- a/include/zlib/zutil.h
+++ b/include/zlib/zutil.h
@@ -1,5 +1,5 @@
 /* zutil.h -- internal interface and configuration of the compression library
- * Copyright (C) 1995-2022 Jean-loup Gailly, Mark Adler
+ * Copyright (C) 1995-2024 Jean-loup Gailly, Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -56,7 +56,7 @@ typedef unsigned long  ulg;
 extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 /* (size given to avoid silly warnings with Visual C++) */
 
-#define ERR_MSG(err) z_errmsg[Z_NEED_DICT-(err)]
+#define ERR_MSG(err) z_errmsg[(err) < -6 || (err) > 2 ? 9 : 2 - (err)]
 
 #define ERR_RETURN(strm,err) \
   return (strm->msg = ERR_MSG(err), (err))
@@ -137,17 +137,8 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #  endif
 #endif
 
-#if defined(MACOS) || defined(TARGET_OS_MAC)
+#if defined(MACOS)
 #  define OS_CODE  7
-#  ifndef Z_SOLO
-#    if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
-#      include <unix.h> /* for fdopen */
-#    else
-#      ifndef fdopen
-#        define fdopen(fd,mode) NULL /* No fdopen() */
-#      endif
-#    endif
-#  endif
 #endif
 
 #ifdef __acorn
@@ -170,18 +161,6 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #  define OS_CODE 19
 #endif
 
-#if defined(_BEOS_) || defined(RISCOS)
-#  define fdopen(fd,mode) NULL /* No fdopen() */
-#endif
-
-#if (defined(_MSC_VER) && (_MSC_VER > 600)) && !defined __INTERIX
-#  if defined(_WIN32_WCE)
-#    define fdopen(fd,mode) NULL /* No fdopen() */
-#  else
-#    define fdopen(fd,type)  _fdopen(fd,type)
-#  endif
-#endif
-
 #if defined(__BORLANDC__) && !defined(MSDOS)
   #pragma warn -8004
   #pragma warn -8008