diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 12d322a8d..d459ab534 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -20,7 +20,7 @@ RUN apt-get update && apt-get install -y \
 
 # install gRPC
 RUN cd / && \
-  git clone --recurse-submodules -b v1.39.0 https://github.com/grpc/grpc && \
+  git clone --recurse-submodules -b v1.49.1 https://github.com/grpc/grpc && \
   cd grpc && \
   mkdir -p cmake/build && \
   cd cmake/build && \
@@ -51,4 +51,3 @@ RUN cd /tmp && \
   make install && \
   ldconfig && \
   rm -rf /tmp/googletest
-
diff --git a/include/mjx/action.cpp b/include/mjx/action.cpp
index b42de9867..21c9a4a92 100644
--- a/include/mjx/action.cpp
+++ b/include/mjx/action.cpp
@@ -4,6 +4,7 @@
 #include <google/protobuf/util/message_differencer.h>
 
 #include <utility>
+#include <optional>
 
 #include "mjx/internal/action.h"
 
diff --git a/include/mjx/action.h b/include/mjx/action.h
index 697329193..7b5e76a31 100644
--- a/include/mjx/action.h
+++ b/include/mjx/action.h
@@ -2,6 +2,7 @@
 #define MJX_PROJECT_ACTION_H
 
 #include "mjx/internal/mjx.grpc.pb.h"
+#include <optional>
 
 namespace mjx {
 class Action {
diff --git a/include/mjx/cmake/downloaded_grpc.cmake b/include/mjx/cmake/downloaded_grpc.cmake
index d7df4aa58..cdda4c6d1 100644
--- a/include/mjx/cmake/downloaded_grpc.cmake
+++ b/include/mjx/cmake/downloaded_grpc.cmake
@@ -30,7 +30,7 @@ set(FETCHCONTENT_UPDATES_DISCONNECTED ON)
 fetchcontent_declare(
   grpc
   GIT_REPOSITORY https://github.com/grpc/grpc.git
-  GIT_TAG v1.39.0
+  GIT_TAG v1.49.1
   GIT_PROGRESS TRUE
 )
 fetchcontent_makeavailable(grpc)
diff --git a/include/mjx/env.cpp b/include/mjx/env.cpp
index f48294381..f77fda01b 100644
--- a/include/mjx/env.cpp
+++ b/include/mjx/env.cpp
@@ -3,6 +3,7 @@
 #include <filesystem>
 #include <fstream>
 #include <utility>
+#include <optional>
 
 namespace mjx {
 
diff --git a/include/mjx/env.h b/include/mjx/env.h
index f0ac190af..57b97d1b2 100644
--- a/include/mjx/env.h
+++ b/include/mjx/env.h
@@ -4,6 +4,7 @@
 #include "mjx/observation.h"
 #include "mjx/seed_generator.h"
 #include "mjx/state.h"
+#include <optional>
 
 #ifndef MJX_PROJECT_ENV_H
 #define MJX_PROJECT_ENV_H
diff --git a/include/mjx/event.cpp b/include/mjx/event.cpp
index b8461d528..8388560be 100644
--- a/include/mjx/event.cpp
+++ b/include/mjx/event.cpp
@@ -4,6 +4,7 @@
 #include <google/protobuf/util/message_differencer.h>
 
 #include <utility>
+#include <optional>
 
 #include "mjx/internal/event.h"
 
diff --git a/include/mjx/event.h b/include/mjx/event.h
index b969b55ad..d86e67208 100644
--- a/include/mjx/event.h
+++ b/include/mjx/event.h
@@ -2,6 +2,7 @@
 #define MJX_PROJECT_EVENT_H
 
 #include "mjx/internal/mjx.grpc.pb.h"
+#include <optional>
 
 namespace mjx {
 class Event {
diff --git a/include/mjx/internal/action.cpp b/include/mjx/internal/action.cpp
index 5d35c4a6c..c99c54258 100644
--- a/include/mjx/internal/action.cpp
+++ b/include/mjx/internal/action.cpp
@@ -3,6 +3,8 @@
 #include "mjx/internal/mjx.grpc.pb.h"
 #include "mjx/internal/utils.h"
 
+#include <optional>
+
 namespace mjx::internal {
 mjxproto::Action Action::CreateDiscard(AbsolutePos who, Tile discard,
                                        std::string game_id) {
diff --git a/include/mjx/internal/action.h b/include/mjx/internal/action.h
index fe208e507..f9c74735f 100644
--- a/include/mjx/internal/action.h
+++ b/include/mjx/internal/action.h
@@ -3,6 +3,7 @@
 
 #include <memory>
 #include <utility>
+#include <optional>
 
 #include "mjx/internal/mjx.pb.h"
 #include "mjx/internal/open.h"
diff --git a/include/mjx/internal/game_result_summarizer.cpp b/include/mjx/internal/game_result_summarizer.cpp
index 5493460b2..f3237d6c5 100644
--- a/include/mjx/internal/game_result_summarizer.cpp
+++ b/include/mjx/internal/game_result_summarizer.cpp
@@ -3,6 +3,8 @@
 namespace mjx::internal {
 std::recursive_mutex GameResultSummarizer::mtx_;
 
+#include <optional>
+
 int GameResultSummarizer::num_games() const { return num_games_; }
 
 void GameResultSummarizer::Initialize() {
diff --git a/include/mjx/internal/game_result_summarizer.h b/include/mjx/internal/game_result_summarizer.h
index 9931dcd4d..e93c3f119 100644
--- a/include/mjx/internal/game_result_summarizer.h
+++ b/include/mjx/internal/game_result_summarizer.h
@@ -3,6 +3,8 @@
 
 #include "mjx/internal/state.h"
 
+#include <optional>
+
 namespace mjx::internal {
 class GameResultSummarizer {
  public:
diff --git a/include/mjx/internal/hand.cpp b/include/mjx/internal/hand.cpp
index c3d6416c5..91bfda2e0 100644
--- a/include/mjx/internal/hand.cpp
+++ b/include/mjx/internal/hand.cpp
@@ -8,6 +8,7 @@
 #include <numeric>
 #include <unordered_map>
 #include <utility>
+#include <optional>
 
 #include "mjx/internal/open.h"
 #include "mjx/internal/utils.h"
diff --git a/include/mjx/internal/hand.h b/include/mjx/internal/hand.h
index a3bad1a09..e4d36384c 100644
--- a/include/mjx/internal/hand.h
+++ b/include/mjx/internal/hand.h
@@ -6,6 +6,7 @@
 #include <unordered_map>
 #include <unordered_set>
 #include <vector>
+#include <optional>
 
 #include "mjx/internal/open.h"
 #include "mjx/internal/tile.h"
diff --git a/include/mjx/internal/observation.cpp b/include/mjx/internal/observation.cpp
index 42a5db8ae..895395f86 100644
--- a/include/mjx/internal/observation.cpp
+++ b/include/mjx/internal/observation.cpp
@@ -5,6 +5,8 @@
 #include "mjx/internal/utils.h"
 #include "mjx/internal/yaku_evaluator.h"
 
+#include <optional>
+
 namespace mjx::internal {
 Observation::Observation(const mjxproto::Observation &proto) : proto_(proto) {}
 
diff --git a/include/mjx/internal/observation.h b/include/mjx/internal/observation.h
index e08f41e5b..8e1306888 100644
--- a/include/mjx/internal/observation.h
+++ b/include/mjx/internal/observation.h
@@ -3,6 +3,7 @@
 
 #include <array>
 #include <utility>
+#include <optional>
 
 #include "mjx/internal/action.h"
 #include "mjx/internal/hand.h"
diff --git a/include/mjx/internal/state.cpp b/include/mjx/internal/state.cpp
index e184288b7..140dac426 100644
--- a/include/mjx/internal/state.cpp
+++ b/include/mjx/internal/state.cpp
@@ -4,6 +4,7 @@
 #include <google/protobuf/util/message_differencer.h>
 
 #include "mjx/internal/utils.h"
+#include <optional>
 
 namespace mjx::internal {
 State::State(State::ScoreInfo score_info)
diff --git a/include/mjx/internal/state.h b/include/mjx/internal/state.h
index f5735475b..4a57ce90e 100644
--- a/include/mjx/internal/state.h
+++ b/include/mjx/internal/state.h
@@ -10,6 +10,7 @@
 #include <string>
 #include <utility>
 #include <vector>
+#include <optional>
 
 #include "mjx/internal/action.h"
 #include "mjx/internal/consts.h"
diff --git a/include/mjx/internal/win_info.h b/include/mjx/internal/win_info.h
index 091b7bbb1..07582516b 100644
--- a/include/mjx/internal/win_info.h
+++ b/include/mjx/internal/win_info.h
@@ -4,6 +4,7 @@
 #include <unordered_set>
 #include <utility>
 #include <vector>
+#include <optional>
 
 #include "mjx/internal/open.h"
 #include "mjx/internal/tile.h"
diff --git a/include/mjx/internal/win_score.cpp b/include/mjx/internal/win_score.cpp
index 7e29ce172..7440b2942 100644
--- a/include/mjx/internal/win_score.cpp
+++ b/include/mjx/internal/win_score.cpp
@@ -1,6 +1,7 @@
 #include "mjx/internal/win_score.h"
 
 #include <utility>
+#include <optional>
 
 #include "mjx/internal/types.h"
 
diff --git a/include/mjx/internal/win_score.h b/include/mjx/internal/win_score.h
index 2a5069709..f3e20ba81 100644
--- a/include/mjx/internal/win_score.h
+++ b/include/mjx/internal/win_score.h
@@ -4,6 +4,7 @@
 #include <array>
 #include <map>
 #include <utility>
+#include <optional>
 
 #include "mjx/internal/types.h"
 
diff --git a/include/mjx/internal/yaku_evaluator.cpp b/include/mjx/internal/yaku_evaluator.cpp
index 0dd0acda6..4f795eb75 100644
--- a/include/mjx/internal/yaku_evaluator.cpp
+++ b/include/mjx/internal/yaku_evaluator.cpp
@@ -3,6 +3,7 @@
 #include <cassert>
 #include <tuple>
 #include <vector>
+#include <optional>
 
 #include "mjx/internal/types.h"
 #include "mjx/internal/utils.h"
diff --git a/include/mjx/internal/yaku_evaluator.h b/include/mjx/internal/yaku_evaluator.h
index 82a1e8040..adcf95372 100644
--- a/include/mjx/internal/yaku_evaluator.h
+++ b/include/mjx/internal/yaku_evaluator.h
@@ -4,6 +4,7 @@
 #include <tuple>
 #include <unordered_set>
 #include <vector>
+#include <optional>
 
 #include "mjx/internal/types.h"
 #include "mjx/internal/win_cache.h"
diff --git a/mjx/pybind.cpp b/mjx/pybind.cpp
index 36a82c0a1..f3cca1c32 100644
--- a/mjx/pybind.cpp
+++ b/mjx/pybind.cpp
@@ -4,6 +4,8 @@
 #include <pybind11/pybind11.h>
 #include <pybind11/stl.h>
 
+#include <optional>
+
 namespace py = pybind11;
 
 // [references]
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 703e7d610..cda5cb25d 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,4 +1,4 @@
-grpcio-tools==1.39.0
+grpcio-tools==1.49.1
 pytest
 black
 blackdoc
diff --git a/requirements.txt b/requirements.txt
index 9ec3e0e02..b6e2b6724 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 google==3.0.0
 protobuf==3.17.3
-grpcio==1.39.0
+grpcio==1.49.1
 numpy
 pillow
 svgwrite
diff --git a/setup.py b/setup.py
index e113d38c8..0346ab115 100644
--- a/setup.py
+++ b/setup.py
@@ -154,7 +154,7 @@ def build_extension(self, ext):
     install_requires=[
         "google==3.0.0",
         "protobuf==3.17.3",
-        "grpcio==1.39.0",
+        "grpcio==1.49.1",
         "numpy",
         "pillow",
         "svgwrite",
diff --git a/tests_cpp/internal_hand_test.cpp b/tests_cpp/internal_hand_test.cpp
index f897d3d50..cac963ec7 100644
--- a/tests_cpp/internal_hand_test.cpp
+++ b/tests_cpp/internal_hand_test.cpp
@@ -2,6 +2,7 @@
 #include <mjx/internal/tile.h>
 
 #include <array>
+#include <optional>
 
 #include "gtest/gtest.h"
 
diff --git a/tests_cpp/internal_win_score_test.cpp b/tests_cpp/internal_win_score_test.cpp
index 71f487d40..579a39eef 100644
--- a/tests_cpp/internal_win_score_test.cpp
+++ b/tests_cpp/internal_win_score_test.cpp
@@ -1,6 +1,7 @@
 #include <mjx/internal/win_score.h>
 
 #include "gtest/gtest.h"
+#include <optional>
 
 using namespace mjx::internal;
 
diff --git a/tests_cpp/internal_yaku_evaluator_test.cpp b/tests_cpp/internal_yaku_evaluator_test.cpp
index 2bb2572d6..3e84bce1a 100644
--- a/tests_cpp/internal_yaku_evaluator_test.cpp
+++ b/tests_cpp/internal_yaku_evaluator_test.cpp
@@ -4,6 +4,8 @@
 
 #include "gtest/gtest.h"
 
+#include <optional>
+
 using namespace mjx::internal;
 
 class YakuTest : public ::testing::Test {