diff --git a/CHANGELOG.md b/CHANGELOG.md
index 998febd40..6699e2329 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,6 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## 5.3.0 - undefined
-
 ### Added
 - Screen Sharing
 
@@ -16,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Call logs synchronization.
 - URI handlers when mixing remote provisioning and call.
 - Blinking on resize or Ui updates on screen that have low frame rates.
+- Timezones and Windows fix.
 
 ## 5.2.2 - 2024-03-11
 
diff --git a/linphone-app/src/app/App.cpp b/linphone-app/src/app/App.cpp
index 0dc8ab966..9d10d371b 100644
--- a/linphone-app/src/app/App.cpp
+++ b/linphone-app/src/app/App.cpp
@@ -273,19 +273,37 @@ App::App(int &argc, char *argv[])
 			SLOT(stateChanged(Qt::ApplicationState)));
 	setWindowIcon(QIcon(Constants::WindowIconPath));
 
-	char *tz = getenv("TZ");
-	if (!tz) { // If not set, set the environement variable for uses of mktime from the SDK.
 #ifdef Q_OS_WIN
-		_putenv(("TZ=" + QTimeZone::systemTimeZoneId().toStdString()).c_str());
-		_tzset();
+	char tz[255] = {0};
+	size_t envSize = 0;
+	getenv_s(&envSize, tz, 255, "TZ");
+	if (envSize == 0 || tz[0] == '\0') { // If not set, set the environment variable for uses of mktime from the SDK.
+		long adjustTimezone;
+		_tzset(); // init timezone variable
+		auto error = _get_timezone(&adjustTimezone);
+		if (adjustTimezone != -QTimeZone::systemTimeZone().offsetFromUtc(QDateTime::currentDateTime())) {
+			QString timeZone = QTimeZone::systemTimeZoneId();
+			_putenv(("TZ=" + timeZone.toStdString()).c_str());
+			_tzset();
+			qInfo() << "Set TimeZone to " << timeZone;
+		}
+	} else qInfo() << "Use environment TimeZone:" << tz;
 #else
-		setenv("TZ", QTimeZone::systemTimeZoneId().toStdString().c_str(), 1);
-		tzset();
+	char *tz = getenv("TZ");
+	if (!tz) {   // If not set, set the environment variable for uses of mktime from the SDK.
+		tzset(); // init timezone variable
+		if (timezone != -QTimeZone::systemTimeZone().offsetFromUtc(QDateTime::currentDateTime())) {
+			QString timeZone = QTimeZone::systemTimeZoneId();
+			setenv("TZ", timeZone.toStdString().c_str(), 1);
+			tzset();
+			qInfo() << "Set TimeZone to " << timeZone;
+		}
+	} else qInfo() << "Use environment TimeZone:" << tz;
 #endif
-	}
-	bctbx_set_default_encoding(
-		Constants::LinphoneLocaleEncoding); // Use UTF-8 for internals. Linphone uses UTF-8 so there will be no loss on
-											// data with less precise encodings. Qt will do the rest.
+
+	// Use UTF-8 for internals. Linphone uses UTF-8 so there will be no loss on
+	// data with less precise encodings. Qt will do the rest.
+	bctbx_set_default_encoding(Constants::LinphoneLocaleEncoding);
 
 	createParser();
 	mParser->parse(this->arguments());