diff --git a/Sources/SHFirestoreService/Combine+FutureHelpers.swift b/Sources/SHFirestoreService/Combine+FutureHelpers.swift
index 7974d9b..ea8ff86 100644
--- a/Sources/SHFirestoreService/Combine+FutureHelpers.swift
+++ b/Sources/SHFirestoreService/Combine+FutureHelpers.swift
@@ -10,6 +10,9 @@ import Foundation
 #if canImport(Combine) && os(iOS) && swift(>=5.0)
 import Combine
 
+@available(swift 5.0)
+@available(iOS 13.0, *)
+
 public extension Publisher
 where Output == Void, Failure == FirestoreServiceError {
   func sink(promise: @escaping Future<Output, Error>.Promise) -> AnyCancellable {
diff --git a/Sources/SHFirestoreService/Combine+Helpers.swift b/Sources/SHFirestoreService/Combine+Helpers.swift
index 07b8857..8d46380 100644
--- a/Sources/SHFirestoreService/Combine+Helpers.swift
+++ b/Sources/SHFirestoreService/Combine+Helpers.swift
@@ -10,6 +10,9 @@ import Foundation
 #if canImport(Combine) && os(iOS) && swift(>=5.0)
 import Combine
 
+@available(swift 5.0)
+@available(iOS 13.0, *)
+
 internal extension Publisher {
   func subscribeAndReceive(
     on queue: DispatchQueue
@@ -17,4 +20,14 @@ internal extension Publisher {
     return self.subscribe(on: queue).receive(on: queue)
   }
 }
+
+internal extension Publisher where Failure == Error {
+  func convertFirestoreServiceError(
+  ) -> Publishers.MapError<Self, FirestoreServiceError> {
+    return self.mapError { error in
+      FirestoreServiceError.wrappedfirestoreError(error)
+    }
+  }
+}
+
 #endif
diff --git a/Sources/SHFirestoreService/SHFirestoreHelpers.swift b/Sources/SHFirestoreService/SHFirestoreHelpers.swift
index 8aee459..75277c0 100644
--- a/Sources/SHFirestoreService/SHFirestoreHelpers.swift
+++ b/Sources/SHFirestoreService/SHFirestoreHelpers.swift
@@ -5,22 +5,17 @@
 //  Created by 양승현 on 4/24/24.
 //
 
+#if os(iOS) && swift(>=5.0)
 import Foundation
-import Combine
 
-internal extension Publisher where Failure == Error {
-  func convertFirestoreServiceError(
-  ) -> Publishers.MapError<Self, FirestoreServiceError> {
-    return self.mapError { error in
-      FirestoreServiceError.wrappedfirestoreError(error)
-    }
-  }
-}
+@available(swift 5.0)
+@available(iOS 13.0, *)
 
 internal extension Encodable {
-  func toDictionary() throws -> [String: Any] {
+  typealias Dictionary = [String: Any]
+  func toDictionary() throws -> Dictionary {
     let data = try JSONEncoder().encode(self)
-    guard let dict = try JSONSerialization.jsonObject(with: data) as? [String: Any] else {
+    guard let dict = try JSONSerialization.jsonObject(with: data) as? Dictionary else {
       throw Swift.EncodingError.invalidValue(
         self,
         Swift.EncodingError.Context.init(
@@ -30,3 +25,5 @@ internal extension Encodable {
     return dict
   }
 }
+
+#endif