diff --git a/GitUpdateChecker.exe b/GitUpdateChecker.exe
index 9dd1984..25b2875 100644
Binary files a/GitUpdateChecker.exe and b/GitUpdateChecker.exe differ
diff --git a/git_updater.py b/git_updater.py
index 278fc8f..cc698e4 100644
--- a/git_updater.py
+++ b/git_updater.py
@@ -5,7 +5,7 @@ Accès lecture seule uniquement (fetch/pull/checkout, jamais de push).
 Tous les chemins sont relatifs à l'emplacement de l'exécutable.
 """
 
-VERSION = "0.5.3"
+VERSION = "0.5.4"
 
 import subprocess
 import sys
@@ -13,6 +13,7 @@ import os
 import configparser
 import logging
 import threading
+from concurrent.futures import ThreadPoolExecutor, as_completed
 import tkinter as tk
 from tkinter import ttk, messagebox
 from pathlib import Path
@@ -108,19 +109,20 @@ def _version_tuple(v):
 
 
 def _get_self_update_config():
-    """Lit la config [self-update] depuis config.ini. Retourne (url, exe_name) ou (None, None)."""
+    """Lit la config [self-update] depuis config.ini. Retourne (url, exe_name, branch) ou (None, None, None)."""
     config_path = get_config_path()
     if not config_path.exists():
-        return None, None
+        return None, None, None
     config = configparser.ConfigParser()
     config.read(config_path, encoding="utf-8")
     if not config.has_section("self-update"):
-        return None, None
+        return None, None, None
     url = config.get("self-update", "url", fallback="").strip().rstrip("/")
     exe_name = config.get("self-update", "exe_name", fallback="GitUpdateChecker.exe").strip()
+    branch = config.get("self-update", "branch", fallback="master").strip()
     if not url:
-        return None, None
-    return url, exe_name
+        return None, None, None
+    return url, exe_name, branch
 
 
 def check_self_update():
@@ -129,14 +131,14 @@ def check_self_update():
     Télécharge version.txt via HTTP et compare avec VERSION locale.
     Retourne (needs_update: bool, info: str).
     """
-    repo_url, _ = _get_self_update_config()
+    repo_url, _, branch = _get_self_update_config()
     if not repo_url:
         log.info("Auto-update: pas de section [self-update] dans config.ini, skip")
         return False, ""
 
     log.info("Auto-update: verification via HTTP...")
 
-    version_url = f"{repo_url}/raw/branch/master/version.txt"
+    version_url = f"{repo_url}/raw/branch/{branch}/version.txt"
     try:
         req = urllib.request.Request(version_url, headers={"User-Agent": "GitUpdateChecker"})
         with urllib.request.urlopen(req, timeout=10) as resp:
@@ -162,7 +164,7 @@ def do_self_update():
     Stratégie : télécharger dans .new, renommer l'exe actuel en .old, placer le nouveau.
     Retourne (ok, message).
     """
-    repo_url, exe_name = _get_self_update_config()
+    repo_url, exe_name, branch = _get_self_update_config()
     if not repo_url:
         return False, "Configuration [self-update] manquante"
 
@@ -176,21 +178,26 @@ def do_self_update():
     exe_new_path = exe_path.with_suffix(".exe.new")
 
     # Telecharger le nouvel exe
-    download_url = f"{repo_url}/raw/branch/master/{exe_name}"
+    download_url = f"{repo_url}/raw/branch/{branch}/{exe_name}"
     log.info(f"Auto-update: telechargement de {download_url}")
 
     try:
         req = urllib.request.Request(download_url, headers={"User-Agent": "GitUpdateChecker"})
-        with urllib.request.urlopen(req, timeout=60) as resp:
-            data = resp.read()
+        total_bytes = 0
+        with urllib.request.urlopen(req, timeout=60) as resp, open(exe_new_path, "wb") as f:
+            while True:
+                chunk = resp.read(65536)  # 64 Ko par bloc
+                if not chunk:
+                    break
+                f.write(chunk)
+                total_bytes += len(chunk)
 
-        if len(data) < 1000:
-            log.error(f"Auto-update: fichier telecharge trop petit ({len(data)} octets)")
+        if total_bytes < 1000:
+            log.error(f"Auto-update: fichier telecharge trop petit ({total_bytes} octets)")
+            exe_new_path.unlink(missing_ok=True)
             return False, "Le fichier telecharge semble invalide"
 
-        with open(exe_new_path, "wb") as f:
-            f.write(data)
-        log.info(f"Auto-update: telecharge {len(data)} octets -> {exe_new_path.name}")
+        log.info(f"Auto-update: telecharge {total_bytes} octets -> {exe_new_path.name}")
 
     except (urllib.error.URLError, OSError) as e:
         log.error(f"Auto-update: echec telechargement: {e}")
@@ -671,10 +678,21 @@ class App(tk.Tk):
         threading.Thread(target=self._check_all, daemon=True).start()
 
     def _check_all(self):
-        """Vérifie tous les repos (dans un thread)."""
-        results = []
-        for repo in self.repos_config:
-            results.append(check_repo(repo))
+        """Vérifie tous les repos en parallèle (max 4 à la fois)."""
+        total = len(self.repos_config)
+        results = [None] * total
+        done = 0
+
+        with ThreadPoolExecutor(max_workers=4) as executor:
+            futures = {executor.submit(check_repo, repo): i for i, repo in enumerate(self.repos_config)}
+            for future in as_completed(futures):
+                idx = futures[future]
+                res = future.result()
+                results[idx] = res
+                done += 1
+                self._log_gui(f"[{res['name']}] Verification terminee", "info")
+                self.after(0, lambda d=done, t=total: self.status_label.configure(text=f"Verification {d}/{t}..."))
+
         self.repo_results = results
         self.after(0, self._display_results)
 
diff --git a/version.txt b/version.txt
index be14282..7d85683 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-0.5.3
+0.5.4