diff --git a/src/main/java/com/javanauta/ts/taskscheduler/business/TaskService.java b/src/main/java/com/javanauta/ts/taskscheduler/business/TaskService.java
index c03cf73..06ac2e3 100644
--- a/src/main/java/com/javanauta/ts/taskscheduler/business/TaskService.java
+++ b/src/main/java/com/javanauta/ts/taskscheduler/business/TaskService.java
@@ -5,13 +5,15 @@
 import com.javanauta.ts.taskscheduler.business.mapper.TaskUpdateConverter;
 import com.javanauta.ts.taskscheduler.infrastructure.entity.Task;
 import com.javanauta.ts.taskscheduler.infrastructure.enums.NotificationStatusEnum;
+import com.javanauta.ts.taskscheduler.infrastructure.exception.InvalidTimeZoneException;
 import com.javanauta.ts.taskscheduler.infrastructure.exception.ResourceNotFoundException;
 import com.javanauta.ts.taskscheduler.infrastructure.repository.TaskRepository;
 import com.javanauta.ts.taskscheduler.infrastructure.security.JwtUtil;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
-import java.time.LocalDateTime;
+import java.time.Instant;
+import java.time.ZoneId;
 import java.util.List;
 
 @Service
@@ -25,16 +27,23 @@ public class TaskService {
 
     public TaskDTO saveTask(String token, TaskDTO taskDTO) {
         taskDTO.setUserEmail(jwtUtil.extractUsername(token.substring(7)));
-        taskDTO.setCreationDateTime(LocalDateTime.now());
+        taskDTO.setCreationDateTime(Instant.now());
         taskDTO.setNotificationStatusEnum(NotificationStatusEnum.PENDING);
+        validateTimeZoneId(taskDTO.getTimeZoneId());
 
         Task task = taskConverter.toTask(taskDTO);
 
         return taskConverter.toTaskDTO(taskRepository.save(task));
     }
 
-    public List<TaskDTO> findTaskByTimePeriod(LocalDateTime initialDateTime, LocalDateTime finalDateTime) {
-        return taskConverter.toTaskDTOList(taskRepository.findByDueDateTimeBetween(initialDateTime, finalDateTime));
+    private void validateTimeZoneId(String timeZoneId) {
+        if (!ZoneId.getAvailableZoneIds().contains(timeZoneId)) {
+            throw new InvalidTimeZoneException("Invalid time zone ID: " + timeZoneId);
+        }
+    }
+
+    public List<TaskDTO> findTaskByTimePeriod(Instant initialDateTime, Instant finalDateTime) {
+        return taskConverter.toTaskDTOList(taskRepository.findByScheduledDateTimeBetween(initialDateTime, finalDateTime));
     }
 
     public List<TaskDTO> findTaskByUserEmail(String token) {
@@ -52,6 +61,7 @@ public void deleteTaskById(String id) {
     public TaskDTO modifyTaskStatusById (NotificationStatusEnum notificationStatusEnum, String id) {
         Task task = taskRepository.findById(id).orElseThrow(() -> new ResourceNotFoundException(String.format("Task with ID '%s' not found.", id)));
         task.setNotificationStatusEnum(notificationStatusEnum);
+        task.setModificationDateTime(Instant.now());
 
         return taskConverter.toTaskDTO(taskRepository.save(task));
     }
@@ -60,6 +70,9 @@ public TaskDTO updateTaskById (TaskDTO taskDTO, String id) {
         Task task = taskRepository.findById(id).orElseThrow(() -> new ResourceNotFoundException(String.format("Task with ID '%s' not found.", id)));
 
         taskUpdateConverter.updateTasks(taskDTO, task);
+        validateTimeZoneId(task.getTimeZoneId());
+        task.setModificationDateTime(Instant.now());
+
         return taskConverter.toTaskDTO(taskRepository.save(task));
     }
 }
diff --git a/src/main/java/com/javanauta/ts/taskscheduler/business/dto/TaskDTO.java b/src/main/java/com/javanauta/ts/taskscheduler/business/dto/TaskDTO.java
index b306202..9504214 100644
--- a/src/main/java/com/javanauta/ts/taskscheduler/business/dto/TaskDTO.java
+++ b/src/main/java/com/javanauta/ts/taskscheduler/business/dto/TaskDTO.java
@@ -1,10 +1,9 @@
 package com.javanauta.ts.taskscheduler.business.dto;
 
-import com.fasterxml.jackson.annotation.JsonFormat;
 import com.javanauta.ts.taskscheduler.infrastructure.enums.NotificationStatusEnum;
 import lombok.*;
 
-import java.time.LocalDateTime;
+import java.time.Instant;
 
 @Getter
 @Setter
@@ -16,12 +15,10 @@ public class TaskDTO {
     private String id;
     private String name;
     private String description;
-    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy HH:mm:ss")
-    private LocalDateTime creationDateTime;
-    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy HH:mm:ss")
-    private LocalDateTime dueDateTime;
+    private Instant creationDateTime;
+    private Instant scheduledDateTime;
     private String userEmail;
-    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy HH:mm:ss")
-    private LocalDateTime modificationDateTime;
+    private Instant modificationDateTime;
     private NotificationStatusEnum notificationStatusEnum;
+    private String timeZoneId;
 }
diff --git a/src/main/java/com/javanauta/ts/taskscheduler/controller/GlobalExceptionHandler.java b/src/main/java/com/javanauta/ts/taskscheduler/controller/GlobalExceptionHandler.java
index 4db8fac..9d8693a 100644
--- a/src/main/java/com/javanauta/ts/taskscheduler/controller/GlobalExceptionHandler.java
+++ b/src/main/java/com/javanauta/ts/taskscheduler/controller/GlobalExceptionHandler.java
@@ -1,5 +1,6 @@
 package com.javanauta.ts.taskscheduler.controller;
 
+import com.javanauta.ts.taskscheduler.infrastructure.exception.InvalidTimeZoneException;
 import com.javanauta.ts.taskscheduler.infrastructure.exception.ResourceNotFoundException;
 import com.javanauta.ts.taskscheduler.infrastructure.exception.UnauthorizedException;
 import org.springframework.http.HttpStatus;
@@ -19,4 +20,9 @@ public ResponseEntity<String> handlerResourceNotFoundException(ResourceNotFoundE
     public ResponseEntity<String> handlerUnauthorizedException(UnauthorizedException ex) {
         return new ResponseEntity<>(ex.getMessage(), HttpStatus.UNAUTHORIZED);
     }
+
+    @ExceptionHandler(InvalidTimeZoneException.class)
+    public ResponseEntity<String> handlerInvalidTimeZoneId(InvalidTimeZoneException ex) {
+        return new ResponseEntity<>(ex.getMessage(), HttpStatus.BAD_REQUEST);
+    }
 }
diff --git a/src/main/java/com/javanauta/ts/taskscheduler/controller/TaskController.java b/src/main/java/com/javanauta/ts/taskscheduler/controller/TaskController.java
index 0032a1f..3eb38a8 100644
--- a/src/main/java/com/javanauta/ts/taskscheduler/controller/TaskController.java
+++ b/src/main/java/com/javanauta/ts/taskscheduler/controller/TaskController.java
@@ -8,6 +8,7 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import java.time.Instant;
 import java.time.LocalDateTime;
 import java.util.List;
 
@@ -24,7 +25,7 @@ public ResponseEntity<TaskDTO> saveTask(@RequestBody TaskDTO taskDTO, @RequestHe
     }
 
     @GetMapping("/events")
-    public ResponseEntity<List<TaskDTO>> findTaskListByPeriod(@RequestParam @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) LocalDateTime initialDateTime, @RequestParam @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) LocalDateTime finalDateTime) {
+    public ResponseEntity<List<TaskDTO>> findTaskListByPeriod(@RequestParam @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) Instant initialDateTime, @RequestParam @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) Instant finalDateTime) {
         return ResponseEntity.ok(taskService.findTaskByTimePeriod(initialDateTime, finalDateTime));
     }
 
diff --git a/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/entity/Task.java b/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/entity/Task.java
index a814029..ef0afeb 100644
--- a/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/entity/Task.java
+++ b/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/entity/Task.java
@@ -5,6 +5,7 @@
 import org.springframework.data.annotation.Id;
 import org.springframework.data.mongodb.core.mapping.Document;
 
+import java.time.Instant;
 import java.time.LocalDateTime;
 
 @Setter
@@ -19,9 +20,10 @@ public class Task {
     private String id;
     private String name;
     private String description;
-    private LocalDateTime creationDateTime;
-    private LocalDateTime dueDateTime;
+    private Instant creationDateTime;
+    private Instant scheduledDateTime;
     private String userEmail;
-    private LocalDateTime modificationDateTime;
+    private Instant modificationDateTime;
     private NotificationStatusEnum notificationStatusEnum;
+    private String timeZoneId;
 }
diff --git a/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/exception/InvalidTimeZoneException.java b/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/exception/InvalidTimeZoneException.java
new file mode 100644
index 0000000..067eab1
--- /dev/null
+++ b/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/exception/InvalidTimeZoneException.java
@@ -0,0 +1,10 @@
+package com.javanauta.ts.taskscheduler.infrastructure.exception;
+
+public class InvalidTimeZoneException extends RuntimeException {
+    public InvalidTimeZoneException(String message) {
+        super(message);
+    }
+    public InvalidTimeZoneException(String message, Throwable throwable) {
+        super(message, throwable);
+    }
+}
diff --git a/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/repository/TaskRepository.java b/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/repository/TaskRepository.java
index c912480..13ea63b 100644
--- a/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/repository/TaskRepository.java
+++ b/src/main/java/com/javanauta/ts/taskscheduler/infrastructure/repository/TaskRepository.java
@@ -4,11 +4,11 @@
 import org.springframework.data.mongodb.repository.MongoRepository;
 import org.springframework.stereotype.Repository;
 
-import java.time.LocalDateTime;
+import java.time.Instant;
 import java.util.List;
 
 @Repository
 public interface TaskRepository extends MongoRepository<Task, String> {
-    List<Task> findByDueDateTimeBetween(LocalDateTime initialDateTime, LocalDateTime finalDateTime);
+    List<Task> findByScheduledDateTimeBetween(Instant initialDateTime, Instant finalDateTime);
     List<Task> findByUserEmail(String userEmail);
 }