diff --git a/Sources/InfomaniakCore/Networking/ApiFetcher.swift b/Sources/InfomaniakCore/Networking/ApiFetcher.swift
index e2374bf..3f18adf 100644
--- a/Sources/InfomaniakCore/Networking/ApiFetcher.swift
+++ b/Sources/InfomaniakCore/Networking/ApiFetcher.swift
@@ -199,8 +199,8 @@ open class ApiFetcher {
         try await perform(request: authenticatedRequest(.organisationAccounts))
     }
 
-    public func userProfile(ignoreDefaultAvatar: Bool = false) async throws -> UserProfile {
-        try await perform(request: authenticatedRequest(.profile(ignoreDefaultAvatar: ignoreDefaultAvatar)))
+    public func userProfile(ignoreDefaultAvatar: Bool = false, dateFormat: DateFormat = .json) async throws -> UserProfile {
+        try await perform(request: authenticatedRequest(.profile(ignoreDefaultAvatar: ignoreDefaultAvatar), headers: ["X-Date-Format": dateFormat.rawValue]))
     }
 }
 
diff --git a/Sources/InfomaniakCore/Networking/DateFormat.swift b/Sources/InfomaniakCore/Networking/DateFormat.swift
new file mode 100644
index 0000000..fc1fd67
--- /dev/null
+++ b/Sources/InfomaniakCore/Networking/DateFormat.swift
@@ -0,0 +1,24 @@
+/*
+ Infomaniak Core - iOS
+ Copyright (C) 2022 Infomaniak Network SA
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import Foundation
+
+public enum DateFormat: String {
+    case iso8601
+    case json = "application/json"
+}