--- a/browser/config/tooltool-manifests/win32/releng.manifest
+++ b/browser/config/tooltool-manifests/win32/releng.manifest
@@ -1,21 +1,21 @@
 [
   {
     "size": 266240,
     "digest": "bb345b0e700ffab4d09436981f14b5de84da55a3f18a7f09ebc4364a4488acdeab8d46f447b12ac70f2da1444a68b8ce8b8675f0dae2ccf845e966d1df0f0869",
     "algorithm": "sha512",
     "filename": "mozmake.exe"
   },
   {
-    "version": "Visual Studio 2017 15.4.1 / SDK 10.0.16299.0",
-    "digest": "b22783f94d8c1304f9640e0cf0c614175c3f2e21f084bb08a31d5b3dc2f387e38a6917170eeb37e6446f191f2d685ca69c5e935f9d18ef41d16abf3a3b981d63",
-    "size": 322544627,
+    "version": "Visual Studio 2017 15.4.2 / SDK 10.0.15063.0",
+    "digest": "18700889e6b5e81613b9cf57ce4e0d46a6ee45bb4c5c33bae2604a5275326128775b8a032a1eb178c5db973746d565340c4e36d98375789e1d5bd836ab16ba58",
+    "size": 303146863,
     "algorithm": "sha512",
-    "filename": "vs2017_15.4.1.zip",
+    "filename": "vs2017_15.4.2.zip",
     "unpack": true
   },
   {
     "version": "makecab rev d2bc6797648b7a834782714a55d339d2fd4e58c8",
     "algorithm": "sha512",
     "visibility": "public",
     "filename": "makecab.tar.bz2",
     "unpack": true,

deleted file mode 100644
--- a/browser/config/tooltool-manifests/win32/vs2017.manifest
+++ /dev/null
@@ -1,25 +0,0 @@
-[
-  {
-    "size": 266240,
-    "digest": "bb345b0e700ffab4d09436981f14b5de84da55a3f18a7f09ebc4364a4488acdeab8d46f447b12ac70f2da1444a68b8ce8b8675f0dae2ccf845e966d1df0f0869",
-    "algorithm": "sha512",
-    "filename": "mozmake.exe"
-  },
-  {
-    "version": "Visual Studio 2017 15.4.1 / SDK 10.0.16299.0",
-    "digest": "b22783f94d8c1304f9640e0cf0c614175c3f2e21f084bb08a31d5b3dc2f387e38a6917170eeb37e6446f191f2d685ca69c5e935f9d18ef41d16abf3a3b981d63",
-    "size": 322544627,
-    "algorithm": "sha512",
-    "filename": "vs2017_15.4.1.zip",
-    "unpack": true
-  },
-  {
-    "version": "makecab rev d2bc6797648b7a834782714a55d339d2fd4e58c8",
-    "algorithm": "sha512",
-    "visibility": "public",
-    "filename": "makecab.tar.bz2",
-    "unpack": true,
-    "digest": "196ac6a567c85559957dfe511c3d8654d23c94d5603259e19ccafe9d71e0e4ccee63ccc9a778f2699654b786cda54266108b7d4db543d01bb0b42545b4e6ec75",
-    "size": 297118
-  }
-]

--- a/browser/config/tooltool-manifests/win64/releng.manifest
+++ b/browser/config/tooltool-manifests/win64/releng.manifest
@@ -1,21 +1,21 @@
 [
   {
     "size": 266240,
     "digest": "bb345b0e700ffab4d09436981f14b5de84da55a3f18a7f09ebc4364a4488acdeab8d46f447b12ac70f2da1444a68b8ce8b8675f0dae2ccf845e966d1df0f0869",
     "algorithm": "sha512",
     "filename": "mozmake.exe"
   },
   {
-    "version": "Visual Studio 2017 15.4.1 / SDK 10.0.16299.0",
-    "digest": "b22783f94d8c1304f9640e0cf0c614175c3f2e21f084bb08a31d5b3dc2f387e38a6917170eeb37e6446f191f2d685ca69c5e935f9d18ef41d16abf3a3b981d63",
-    "size": 322544627,
+    "version": "Visual Studio 2017 15.4.2 / SDK 10.0.15063.0",
+    "digest": "18700889e6b5e81613b9cf57ce4e0d46a6ee45bb4c5c33bae2604a5275326128775b8a032a1eb178c5db973746d565340c4e36d98375789e1d5bd836ab16ba58",
+    "size": 303146863,
     "algorithm": "sha512",
-    "filename": "vs2017_15.4.1.zip",
+    "filename": "vs2017_15.4.2.zip",
     "unpack": true
   },
   {
     "version": "makecab rev d2bc6797648b7a834782714a55d339d2fd4e58c8",
     "algorithm": "sha512",
     "visibility": "public",
     "filename": "makecab.tar.bz2",
     "unpack": true,

deleted file mode 100644
--- a/browser/config/tooltool-manifests/win64/vs2017.manifest
+++ /dev/null
@@ -1,25 +0,0 @@
-[
-  {
-    "size": 266240,
-    "digest": "bb345b0e700ffab4d09436981f14b5de84da55a3f18a7f09ebc4364a4488acdeab8d46f447b12ac70f2da1444a68b8ce8b8675f0dae2ccf845e966d1df0f0869",
-    "algorithm": "sha512",
-    "filename": "mozmake.exe"
-  },
-  {
-    "version": "Visual Studio 2017 15.4.1 / SDK 10.0.16299.0",
-    "digest": "b22783f94d8c1304f9640e0cf0c614175c3f2e21f084bb08a31d5b3dc2f387e38a6917170eeb37e6446f191f2d685ca69c5e935f9d18ef41d16abf3a3b981d63",
-    "size": 322544627,
-    "algorithm": "sha512",
-    "filename": "vs2017_15.4.1.zip",
-    "unpack": true
-  },
-  {
-    "version": "makecab rev d2bc6797648b7a834782714a55d339d2fd4e58c8",
-    "algorithm": "sha512",
-    "visibility": "public",
-    "filename": "makecab.tar.bz2",
-    "unpack": true,
-    "digest": "196ac6a567c85559957dfe511c3d8654d23c94d5603259e19ccafe9d71e0e4ccee63ccc9a778f2699654b786cda54266108b7d4db543d01bb0b42545b4e6ec75",
-    "size": 297118
-  }
-]

--- a/build/win32/mozconfig.vs2017
+++ b/build/win32/mozconfig.vs2017
@@ -1,25 +1,25 @@
 if [ -z "${VSPATH}" ]; then
     TOOLTOOL_DIR=${TOOLTOOL_DIR:-$topsrcdir}
-    VSPATH="$(cd ${TOOLTOOL_DIR} && pwd)/vs2017_15.4.1"
+    VSPATH="$(cd ${TOOLTOOL_DIR} && pwd)/vs2017_15.4.2"
 fi
 
 if [ -d "${VSPATH}" ]; then
     VSWINPATH="$(cd ${VSPATH} && pwd -W)"
 
     export WINDOWSSDKDIR="${VSWINPATH}/SDK"
     export WIN32_REDIST_DIR="${VSPATH}/VC/redist/x86/Microsoft.VC141.CRT"
     export WIN_UCRT_REDIST_DIR="${VSPATH}/SDK/Redist/ucrt/DLLs/x86"
 
-    export PATH="${VSPATH}/VC/bin/Hostx86/x86:${VSPATH}/VC/bin/Hostx64/x86:${VSPATH}/VC/bin/Hostx64/x64:${VSPATH}/SDK/bin/10.0.16299.0/x64:${VSPATH}/DIA SDK/bin:${PATH}"
+    export PATH="${VSPATH}/VC/bin/Hostx86/x86:${VSPATH}/VC/bin/Hostx64/x86:${VSPATH}/VC/bin/Hostx64/x64:${VSPATH}/SDK/bin/10.0.15063.0/x64:${VSPATH}/DIA SDK/bin:${PATH}"
     export PATH="${VSPATH}/VC/redist/x86/Microsoft.VC141.CRT:${VSPATH}/SDK/Redist/ucrt/DLLs/x86:${PATH}"
 
-    export INCLUDE="${VSPATH}/VC/include:${VSPATH}/VC/atlmfc/include:${VSPATH}/SDK/Include/10.0.16299.0/ucrt:${VSPATH}/SDK/Include/10.0.16299.0/shared:${VSPATH}/SDK/Include/10.0.16299.0/um:${VSPATH}/SDK/Include/10.0.16299.0/winrt:${VSPATH}/DIA SDK/include"
-    export LIB="${VSPATH}/VC/lib/x86:${VSPATH}/VC/atlmfc/lib/x86:${VSPATH}/SDK/Lib/10.0.16299.0/ucrt/x86:${VSPATH}/SDK/Lib/10.0.16299.0/um/x86:${VSPATH}/DIA SDK/lib"
+    export INCLUDE="${VSPATH}/VC/include:${VSPATH}/VC/atlmfc/include:${VSPATH}/SDK/Include/10.0.15063.0/ucrt:${VSPATH}/SDK/Include/10.0.15063.0/shared:${VSPATH}/SDK/Include/10.0.15063.0/um:${VSPATH}/SDK/Include/10.0.15063.0/winrt:${VSPATH}/DIA SDK/include"
+    export LIB="${VSPATH}/VC/lib/x86:${VSPATH}/VC/atlmfc/lib/x86:${VSPATH}/SDK/Lib/10.0.15063.0/ucrt/x86:${VSPATH}/SDK/Lib/10.0.15063.0/um/x86:${VSPATH}/DIA SDK/lib"
 fi
 
 . $topsrcdir/build/mozconfig.vs-common
 
 mk_export_correct_style WINDOWSSDKDIR
 mk_export_correct_style WIN32_REDIST_DIR
 mk_export_correct_style WIN_UCRT_REDIST_DIR
 mk_export_correct_style PATH

--- a/build/win64/mozconfig.vs2017
+++ b/build/win64/mozconfig.vs2017
@@ -1,24 +1,24 @@
 if [ -z "${VSPATH}" ]; then
     TOOLTOOL_DIR=${TOOLTOOL_DIR:-$topsrcdir}
-    VSPATH="$(cd ${TOOLTOOL_DIR} && pwd)/vs2017_15.4.1"
+    VSPATH="$(cd ${TOOLTOOL_DIR} && pwd)/vs2017_15.4.2"
 fi
 
 if [ -d "${VSPATH}" ]; then
     VSWINPATH="$(cd ${VSPATH} && pwd -W)"
 
     export WINDOWSSDKDIR="${VSWINPATH}/SDK"
     export WIN32_REDIST_DIR=${VSPATH}/VC/redist/x64/Microsoft.VC141.CRT
     export WIN_UCRT_REDIST_DIR="${VSPATH}/SDK/Redist/ucrt/DLLs/x64"
 
-    export PATH="${VSPATH}/VC/bin/Hostx64/x64:${VSPATH}/SDK/bin/10.0.16299.0/x64:${VSPATH}/VC/redist/x64/Microsoft.VC141.CRT:${VSPATH}/SDK/Redist/ucrt/DLLs/x64:${VSPATH}/DIA SDK/bin/amd64:${PATH}"
+    export PATH="${VSPATH}/VC/bin/Hostx64/x64:${VSPATH}/SDK/bin/10.0.15063.0/x64:${VSPATH}/VC/redist/x64/Microsoft.VC141.CRT:${VSPATH}/SDK/Redist/ucrt/DLLs/x64:${VSPATH}/DIA SDK/bin/amd64:${PATH}"
 
-    export INCLUDE="${VSPATH}/VC/include:${VSPATH}/VC/atlmfc/include:${VSPATH}/SDK/Include/10.0.16299.0/ucrt:${VSPATH}/SDK/Include/10.0.16299.0/shared:${VSPATH}/SDK/Include/10.0.16299.0/um:${VSPATH}/SDK/Include/10.0.16299.0/winrt:${VSPATH}/DIA SDK/include"
-    export LIB="${VSPATH}/VC/lib/x64:${VSPATH}/VC/atlmfc/lib/x64:${VSPATH}/SDK/Lib/10.0.16299.0/ucrt/x64:${VSPATH}/SDK/Lib/10.0.16299.0/um/x64:${VSPATH}/DIA SDK/lib/amd64"
+    export INCLUDE="${VSPATH}/VC/include:${VSPATH}/VC/atlmfc/include:${VSPATH}/SDK/Include/10.0.15063.0/ucrt:${VSPATH}/SDK/Include/10.0.15063.0/shared:${VSPATH}/SDK/Include/10.0.15063.0/um:${VSPATH}/SDK/Include/10.0.15063.0/winrt:${VSPATH}/DIA SDK/include"
+    export LIB="${VSPATH}/VC/lib/x64:${VSPATH}/VC/atlmfc/lib/x64:${VSPATH}/SDK/Lib/10.0.15063.0/ucrt/x64:${VSPATH}/SDK/Lib/10.0.15063.0/um/x64:${VSPATH}/DIA SDK/lib/amd64"
 fi
 
 . $topsrcdir/build/mozconfig.vs-common
 
 mk_export_correct_style WINDOWSSDKDIR
 mk_export_correct_style WIN32_REDIST_DIR
 mk_export_correct_style WIN_UCRT_REDIST_DIR
 mk_export_correct_style PATH

--- a/js/src/devtools/automation/winbuildenv.sh
+++ b/js/src/devtools/automation/winbuildenv.sh
@@ -5,17 +5,17 @@ mk_add_options() {
   echo "$@"
 }
 
 topsrcdir="$SOURCE"
 
 # Tooltool installs in parent of topsrcdir for spidermonkey builds.
 # Resolve that path since the mozconfigs assume tooltool installs in
 # topsrcdir.
-export VSPATH="$(cd ${topsrcdir}/.. && pwd)/vs2017_15.4.1"
+export VSPATH="$(cd ${topsrcdir}/.. && pwd)/vs2017_15.4.2"
 
 # When running on a developer machine, several variables will already
 # have the right settings and we will need to keep them since the
 # Windows mozconfigs overwrite them.
 echo "export ORIGINAL_INCLUDE=$INCLUDE"
 echo "export ORIGINAL_LIB=$LIB"
 echo "export ORIGINAL_LIBPATH=$LIBPATH"