diff --git a/README.md b/README.md
index be61dab..32d086d 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ DataGSM의 OpenAPI를 추상화된 환경에서 제공합니다.
 <dependency>
     <groupId>com.github.themoment-team</groupId>
     <artifactId>datagsm-openapi-sdk-java</artifactId>
-    <version>1.1.1</version>
+    <version>1.3.0</version>
 </dependency>
 ```
 ### 설치 - Gradle
@@ -27,7 +27,7 @@ repositories {
 }
 
 dependencies {
-    implementation 'com.github.themoment-team:datagsm-openapi-sdk-java:1.1.1'
+    implementation 'com.github.themoment-team:datagsm-openapi-sdk-java:1.3.0'
 }
 ```
 
@@ -38,7 +38,7 @@ repositories {
 }
 
 dependencies {
-    implementation("com.github.themoment-team:datagsm-openapi-sdk-java:1.1.1")
+    implementation("com.github.themoment-team:datagsm-openapi-sdk-java:1.3.0")
 }
 ```
 
diff --git a/build.gradle.kts b/build.gradle.kts
index 19555b2..d80c16d 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -4,7 +4,7 @@ plugins {
 }
 
 group = "team.themoment.datagsm.sdk"
-version = "1.2.0"
+version = "1.3.0"
 
 java {
     toolchain {
diff --git a/src/main/java/team/themoment/datagsm/sdk/openapi/model/ClubDetail.java b/src/main/java/team/themoment/datagsm/sdk/openapi/model/ClubDetail.java
index f1aef62..f9b11b6 100644
--- a/src/main/java/team/themoment/datagsm/sdk/openapi/model/ClubDetail.java
+++ b/src/main/java/team/themoment/datagsm/sdk/openapi/model/ClubDetail.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 /**
  * 동아리 상세 정보
@@ -39,8 +40,12 @@ public void setType(ClubType type) {
         this.type = type;
     }
 
-    public ParticipantInfo getLeader() {
-        return leader;
+    /**
+     * 동아리 부장 정보를 반환합니다.
+     * 부장이 자퇴 또는 졸업 처리된 경우 비어 있을 수 있습니다.
+     */
+    public Optional<ParticipantInfo> getLeader() {
+        return Optional.ofNullable(leader);
     }
 
     public void setLeader(ParticipantInfo leader) {
diff --git a/src/main/java/team/themoment/datagsm/sdk/openapi/model/Meal.java b/src/main/java/team/themoment/datagsm/sdk/openapi/model/Meal.java
index c54e36b..4f4fa69 100644
--- a/src/main/java/team/themoment/datagsm/sdk/openapi/model/Meal.java
+++ b/src/main/java/team/themoment/datagsm/sdk/openapi/model/Meal.java
@@ -3,6 +3,7 @@
 import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 /**
  * 급식 정보
@@ -88,40 +89,40 @@ public void setMealMenu(List<String> mealMenu) {
         this.mealMenu = mealMenu;
     }
 
-    public List<String> getMealAllergyInfo() {
-        return mealAllergyInfo;
+    public Optional<List<String>> getMealAllergyInfo() {
+        return Optional.ofNullable(mealAllergyInfo);
     }
 
     public void setMealAllergyInfo(List<String> mealAllergyInfo) {
         this.mealAllergyInfo = mealAllergyInfo;
     }
 
-    public String getMealCalories() {
-        return mealCalories;
+    public Optional<String> getMealCalories() {
+        return Optional.ofNullable(mealCalories);
     }
 
     public void setMealCalories(String mealCalories) {
         this.mealCalories = mealCalories;
     }
 
-    public String getOriginInfo() {
-        return originInfo;
+    public Optional<String> getOriginInfo() {
+        return Optional.ofNullable(originInfo);
     }
 
     public void setOriginInfo(String originInfo) {
         this.originInfo = originInfo;
     }
 
-    public String getNutritionInfo() {
-        return nutritionInfo;
+    public Optional<String> getNutritionInfo() {
+        return Optional.ofNullable(nutritionInfo);
     }
 
     public void setNutritionInfo(String nutritionInfo) {
         this.nutritionInfo = nutritionInfo;
     }
 
-    public Integer getMealServeCount() {
-        return mealServeCount;
+    public Optional<Integer> getMealServeCount() {
+        return Optional.ofNullable(mealServeCount);
     }
 
     public void setMealServeCount(Integer mealServeCount) {
diff --git a/src/main/java/team/themoment/datagsm/sdk/openapi/model/ParticipantInfo.java b/src/main/java/team/themoment/datagsm/sdk/openapi/model/ParticipantInfo.java
index 337041a..e57b404 100644
--- a/src/main/java/team/themoment/datagsm/sdk/openapi/model/ParticipantInfo.java
+++ b/src/main/java/team/themoment/datagsm/sdk/openapi/model/ParticipantInfo.java
@@ -1,5 +1,7 @@
 package team.themoment.datagsm.sdk.openapi.model;
 
+import java.util.Optional;
+
 /**
  * 동아리 부원 정보
  */
@@ -37,16 +39,16 @@ public void setEmail(String email) {
         this.email = email;
     }
 
-    public Integer getStudentNumber() {
-        return studentNumber;
+    public Optional<Integer> getStudentNumber() {
+        return Optional.ofNullable(studentNumber);
     }
 
     public void setStudentNumber(Integer studentNumber) {
         this.studentNumber = studentNumber;
     }
 
-    public Major getMajor() {
-        return major;
+    public Optional<Major> getMajor() {
+        return Optional.ofNullable(major);
     }
 
     public void setMajor(Major major) {
diff --git a/src/main/java/team/themoment/datagsm/sdk/openapi/model/Project.java b/src/main/java/team/themoment/datagsm/sdk/openapi/model/Project.java
index 29f9c75..e16678a 100644
--- a/src/main/java/team/themoment/datagsm/sdk/openapi/model/Project.java
+++ b/src/main/java/team/themoment/datagsm/sdk/openapi/model/Project.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 /**
  * 프로젝트 정보
@@ -39,8 +40,8 @@ public void setDescription(String description) {
         this.description = description;
     }
 
-    public Club getClub() {
-        return club;
+    public Optional<Club> getClub() {
+        return Optional.ofNullable(club);
     }
 
     public void setClub(Club club) {
diff --git a/src/main/java/team/themoment/datagsm/sdk/openapi/model/Schedule.java b/src/main/java/team/themoment/datagsm/sdk/openapi/model/Schedule.java
index 7386088..b0f8d6e 100644
--- a/src/main/java/team/themoment/datagsm/sdk/openapi/model/Schedule.java
+++ b/src/main/java/team/themoment/datagsm/sdk/openapi/model/Schedule.java
@@ -3,6 +3,7 @@
 import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 /**
  * 학사일정 정보
@@ -88,32 +89,32 @@ public void setEventName(String eventName) {
         this.eventName = eventName;
     }
 
-    public String getEventContent() {
-        return eventContent;
+    public Optional<String> getEventContent() {
+        return Optional.ofNullable(eventContent);
     }
 
     public void setEventContent(String eventContent) {
         this.eventContent = eventContent;
     }
 
-    public String getDayCategory() {
-        return dayCategory;
+    public Optional<String> getDayCategory() {
+        return Optional.ofNullable(dayCategory);
     }
 
     public void setDayCategory(String dayCategory) {
         this.dayCategory = dayCategory;
     }
 
-    public String getSchoolCourseType() {
-        return schoolCourseType;
+    public Optional<String> getSchoolCourseType() {
+        return Optional.ofNullable(schoolCourseType);
     }
 
     public void setSchoolCourseType(String schoolCourseType) {
         this.schoolCourseType = schoolCourseType;
     }
 
-    public String getDayNightType() {
-        return dayNightType;
+    public Optional<String> getDayNightType() {
+        return Optional.ofNullable(dayNightType);
     }
 
     public void setDayNightType(String dayNightType) {
diff --git a/src/main/java/team/themoment/datagsm/sdk/openapi/model/Student.java b/src/main/java/team/themoment/datagsm/sdk/openapi/model/Student.java
index 6e4f4dc..f3e43b1 100644
--- a/src/main/java/team/themoment/datagsm/sdk/openapi/model/Student.java
+++ b/src/main/java/team/themoment/datagsm/sdk/openapi/model/Student.java
@@ -1,5 +1,7 @@
 package team.themoment.datagsm.sdk.openapi.model;
 
+import java.util.Optional;
+
 /**
  * 학생 정보
  */
@@ -54,40 +56,40 @@ public void setEmail(String email) {
         this.email = email;
     }
 
-    public Integer getGrade() {
-        return grade;
+    public Optional<Integer> getGrade() {
+        return Optional.ofNullable(grade);
     }
 
     public void setGrade(Integer grade) {
         this.grade = grade;
     }
 
-    public Integer getClassNum() {
-        return classNum;
+    public Optional<Integer> getClassNum() {
+        return Optional.ofNullable(classNum);
     }
 
     public void setClassNum(Integer classNum) {
         this.classNum = classNum;
     }
 
-    public Integer getNumber() {
-        return number;
+    public Optional<Integer> getNumber() {
+        return Optional.ofNullable(number);
     }
 
     public void setNumber(Integer number) {
         this.number = number;
     }
 
-    public Integer getStudentNumber() {
-        return studentNumber;
+    public Optional<Integer> getStudentNumber() {
+        return Optional.ofNullable(studentNumber);
     }
 
     public void setStudentNumber(Integer studentNumber) {
         this.studentNumber = studentNumber;
     }
 
-    public Major getMajor() {
-        return major;
+    public Optional<Major> getMajor() {
+        return Optional.ofNullable(major);
     }
 
     public void setMajor(Major major) {
@@ -102,40 +104,40 @@ public void setRole(StudentRole role) {
         this.role = role;
     }
 
-    public Integer getDormitoryFloor() {
-        return dormitoryFloor;
+    public Optional<Integer> getDormitoryFloor() {
+        return Optional.ofNullable(dormitoryFloor);
     }
 
     public void setDormitoryFloor(Integer dormitoryFloor) {
         this.dormitoryFloor = dormitoryFloor;
     }
 
-    public Integer getDormitoryRoom() {
-        return dormitoryRoom;
+    public Optional<Integer> getDormitoryRoom() {
+        return Optional.ofNullable(dormitoryRoom);
     }
 
     public void setDormitoryRoom(Integer dormitoryRoom) {
         this.dormitoryRoom = dormitoryRoom;
     }
 
-    public Club getMajorClub() {
-        return majorClub;
+    public Optional<Club> getMajorClub() {
+        return Optional.ofNullable(majorClub);
     }
 
     public void setMajorClub(Club majorClub) {
         this.majorClub = majorClub;
     }
 
-    public Club getJobClub() {
-        return jobClub;
+    public Optional<Club> getJobClub() {
+        return Optional.ofNullable(jobClub);
     }
 
     public void setJobClub(Club jobClub) {
         this.jobClub = jobClub;
     }
 
-    public Club getAutonomousClub() {
-        return autonomousClub;
+    public Optional<Club> getAutonomousClub() {
+        return Optional.ofNullable(autonomousClub);
     }
 
     public void setAutonomousClub(Club autonomousClub) {