diff --git a/Makefile b/Makefile
index b075b52..a6f197d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 # Makefile for compiling protobuf files
 
 # Tool versions
-BUF_VERSION = 1.15.0
+BUF_VERSION = 1.30.0
 GO_VERSION := $(shell awk '/^go / {print $$2}' go.mod)
 PROTOC_GEN_GO_VERSION := $(shell awk '/google.golang.org\/protobuf/ {print substr($$NF, 2)}' go.mod)
 
diff --git a/cybozu/validate/options.pb.go b/cybozu/validate/options.pb.go
index 97d59d2..ed9b588 100644
--- a/cybozu/validate/options.pb.go
+++ b/cybozu/validate/options.pb.go
@@ -1,6 +1,6 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.32.0
+// 	protoc-gen-go v1.33.0
 // 	protoc        (unknown)
 // source: cybozu/validate/options.proto
 
diff --git a/examples/validation.pb.go b/examples/validation.pb.go
index 7bcb3b1..e499397 100644
--- a/examples/validation.pb.go
+++ b/examples/validation.pb.go
@@ -1,6 +1,6 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.32.0
+// 	protoc-gen-go v1.33.0
 // 	protoc        (unknown)
 // source: examples/validation.proto
 
diff --git a/go.mod b/go.mod
index 1305f58..18cfef8 100644
--- a/go.mod
+++ b/go.mod
@@ -1,13 +1,13 @@
 module github.com/cybozu/protobuf
 
-go 1.21
+go 1.22
 
-toolchain go1.21.1
+toolchain go1.22.1
 
 require (
-	github.com/stretchr/testify v1.8.4
+	github.com/stretchr/testify v1.9.0
 	golang.org/x/text v0.14.0
-	google.golang.org/protobuf v1.32.0
+	google.golang.org/protobuf v1.33.0
 )
 
 require (
diff --git a/go.sum b/go.sum
index 2e11b73..830c793 100644
--- a/go.sum
+++ b/go.sum
@@ -4,14 +4,14 @@ github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-google.golang.org/protobuf v1.32.0 h1:pPC6BG5ex8PDFnkbrGU3EixyhKcQ2aDuBS36lqK/C7I=
-google.golang.org/protobuf v1.32.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
+google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
+google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=