diff --git a/.gitmodules b/.gitmodules
index c14bb9c5..b3e42f81 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -33,3 +33,7 @@
 [submodule "third_party/mbedtls"]
 	path = third_party/mbedtls
 	url = https://github.com/ARMmbed/mbedtls
+[submodule "third_party/json"]
+	path = third_party/json
+	url = https://github.com/nlohmann/json
+	branch = master
diff --git a/third_party/absl b/third_party/absl
index 9336be04..29273402 160000
--- a/third_party/absl
+++ b/third_party/absl
@@ -1 +1 @@
-Subproject commit 9336be04a242237cd41a525bedfcf3be1bb55377
+Subproject commit 2927340217c37328319b5869285a6dcdbc13e7a7
diff --git a/third_party/depot_tools b/third_party/depot_tools
index e1197f06..95a28c5a 160000
--- a/third_party/depot_tools
+++ b/third_party/depot_tools
@@ -1 +1 @@
-Subproject commit e1197f06a8f45c0328d341b30e337d3a4b609716
+Subproject commit 95a28c5a14cf0c7040794e10e9404b270784010c
diff --git a/third_party/google-toolbox-for-mac/google-toolbox-for-mac b/third_party/google-toolbox-for-mac/google-toolbox-for-mac
index 33941504..1b2da5e6 160000
--- a/third_party/google-toolbox-for-mac/google-toolbox-for-mac
+++ b/third_party/google-toolbox-for-mac/google-toolbox-for-mac
@@ -1 +1 @@
-Subproject commit 339415048005a9eba957357a02459a977a2e3007
+Subproject commit 1b2da5e6e6b5edb1fa1427cc77e23f04069c04ad
diff --git a/third_party/gtest b/third_party/gtest
index d61d4d8e..8fa9461c 160000
--- a/third_party/gtest
+++ b/third_party/gtest
@@ -1 +1 @@
-Subproject commit d61d4d8e64c08a662055e82904bbf90e108a704f
+Subproject commit 8fa9461cc28e053d66f17132808d287ae51575e2
diff --git a/third_party/json b/third_party/json
new file mode 160000
index 00000000..bc889afb
--- /dev/null
+++ b/third_party/json
@@ -0,0 +1 @@
+Subproject commit bc889afb4c5bf1c0d8ee29ef35eaaf4c8bef8a5d
diff --git a/third_party/mbedtls b/third_party/mbedtls
index 3e0418fe..6a327a5f 160000
--- a/third_party/mbedtls
+++ b/third_party/mbedtls
@@ -1 +1 @@
-Subproject commit 3e0418fe502b2a2194e118d362efdfc0e558be73
+Subproject commit 6a327a5fdc2786cb50b4dbe5e3a75884a1f8435a
diff --git a/third_party/protobuf b/third_party/protobuf
index 4812107b..53515ead 160000
--- a/third_party/protobuf
+++ b/third_party/protobuf
@@ -1 +1 @@
-Subproject commit 4812107b9d0fb9fdcca933766c237c38f2150379
+Subproject commit 53515eadce8d732bc0b2d0f0c8ec20ddd55ef86b