diff --git a/embulk-guess-csv/gradle.lockfile b/embulk-guess-csv/gradle.lockfile
index 171189ff..395006e7 100644
--- a/embulk-guess-csv/gradle.lockfile
+++ b/embulk-guess-csv/gradle.lockfile
@@ -15,7 +15,7 @@ org.embulk:embulk-util-guess:0.4.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-json:0.5.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-rubytime:0.4.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-text:0.2.0=compileClasspath,runtimeClasspath
-org.embulk:embulk-util-timestamp:0.3.0=compileClasspath,runtimeClasspath
+org.embulk:embulk-util-timestamp:0.3.1=compileClasspath,runtimeClasspath
 org.msgpack:msgpack-core:0.8.24=compileClasspath
 org.slf4j:slf4j-api:2.0.7=compileClasspath
 empty=
diff --git a/embulk-guess-csv_all_strings/gradle.lockfile b/embulk-guess-csv_all_strings/gradle.lockfile
index 171189ff..395006e7 100644
--- a/embulk-guess-csv_all_strings/gradle.lockfile
+++ b/embulk-guess-csv_all_strings/gradle.lockfile
@@ -15,7 +15,7 @@ org.embulk:embulk-util-guess:0.4.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-json:0.5.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-rubytime:0.4.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-text:0.2.0=compileClasspath,runtimeClasspath
-org.embulk:embulk-util-timestamp:0.3.0=compileClasspath,runtimeClasspath
+org.embulk:embulk-util-timestamp:0.3.1=compileClasspath,runtimeClasspath
 org.msgpack:msgpack-core:0.8.24=compileClasspath
 org.slf4j:slf4j-api:2.0.7=compileClasspath
 empty=
diff --git a/gradle.lockfile b/gradle.lockfile
index 8499cc0c..515e18c3 100644
--- a/gradle.lockfile
+++ b/gradle.lockfile
@@ -14,7 +14,7 @@ org.embulk:embulk-util-file:0.2.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-json:0.5.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-rubytime:0.4.0=compileClasspath,runtimeClasspath
 org.embulk:embulk-util-text:0.2.0=compileClasspath,runtimeClasspath
-org.embulk:embulk-util-timestamp:0.3.0=compileClasspath,runtimeClasspath
+org.embulk:embulk-util-timestamp:0.3.1=compileClasspath,runtimeClasspath
 org.msgpack:msgpack-core:0.8.24=compileClasspath
 org.slf4j:slf4j-api:2.0.7=compileClasspath
 empty=
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 9f1cfa0f..416f3c06 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -19,7 +19,7 @@ embulk-util-guess = "0.4.0"
 embulk-util-json = "0.5.0"
 embulk-util-text = "0.2.0"
 embulk-util-rubytime = "0.4.0"
-embulk-util-timestamp = "0.3.0"
+embulk-util-timestamp = "0.3.1"
 
 junit4 = "4.13.2"
 embulk-core = "0.11.0"