diff --git a/src/libImaging/TiffDecode.c b/src/libImaging/TiffDecode.c
index f33cbc6bd61..d86a42915b7 100644
--- a/src/libImaging/TiffDecode.c
+++ b/src/libImaging/TiffDecode.c
@@ -378,7 +378,7 @@ int ImagingLibTiffDecode(Imaging im, ImagingCodecState state, UINT8* buffer, Py_
             TIFFClose(tiff);
             return -1;
         }
-        
+
         state->bytes = row_byte_size * tile_length;
 
         if (TIFFTileSize(tiff) > state->bytes) {
@@ -578,7 +578,7 @@ int ImagingLibTiffMergeFieldInfo(ImagingCodecState state, TIFFDataType field_typ
 
     // custom fields added with ImagingLibTiffMergeFieldInfo are only used for
     // decoding, ignore readcount;
-    int readcount = 0;
+    int readcount = 1;
     // we support writing a single value, or a variable number of values
     int writecount = 1;
     // whether the first value should encode the number of values.
diff --git a/winbuild/build_prepare.py b/winbuild/build_prepare.py
index fb52cb4ce72..2531d550480 100644
--- a/winbuild/build_prepare.py
+++ b/winbuild/build_prepare.py
@@ -141,9 +141,9 @@ def cmd_msbuild(
         "libs": [r"*.lib"],
     },
     "libtiff": {
-        "url": "https://download.osgeo.org/libtiff/tiff-4.1.0.tar.gz",
-        "filename": "tiff-4.1.0.tar.gz",
-        "dir": "tiff-4.1.0",
+        "url": "https://download.osgeo.org/libtiff/tiff-4.2.0.tar.gz",
+        "filename": "tiff-4.2.0.tar.gz",
+        "dir": "tiff-4.2.0",
         "build": [
             cmd_copy(r"{winbuild_dir}\tiff.opt", "nmake.opt"),
             cmd_nmake("makefile.vc", "clean"),
diff --git a/winbuild/tiff.opt b/winbuild/tiff.opt
index 16acabc26de..d82c51678d6 100644
--- a/winbuild/tiff.opt
+++ b/winbuild/tiff.opt
@@ -66,6 +66,10 @@ ZIP_SUPPORT	= 1
 ZLIB_INCLUDE	= -I$(INCLIB)
 ZLIB_LIB 	= $(INCLIB)/zlib.lib
 
+# Indicate if the compiler provides strtoll/strtoull (default 1)
+# Users of MSVC++ 14.0 ("Visual Studio 2015") and later should set this to 1
+HAVE_STRTOLL = 1
+
 #
 # Uncomment and edit following lines to enable ISO JBIG support
 #