Add executable versioning support for Windows builds

- Implemented `set_exe_version` method in `WindowsBuilder` to set the version information for the generated executable.
- This ensures proper MSI updates by comparing file versions.
- Added error handling for missing `pefile` dependency and version resource.
- Updated `requirements-dev.txt` to include `pefile` as a dependency for building.

DEVELOPMENT_PLAN.md

@@ -1220,6 +1220,14 @@ Phase 4 Complete - Professional Features & Auto-Update system fully implemented
 - ✅ Phase 4.3: Advanced Configuration & Settings UI (43 tests)
 - ✅ Total Phase 4: 139 tests passing, 90%+ coverage
 
+**MSI Update Support (Feb 20, 2026):**
+- ✅ Added `<MajorUpgrade />` element to WiX configuration (build/WebDropBridge.wxs)
+- ✅ Configured `Schedule="afterInstallInitialize"` for safe upgrade flow
+- ✅ Implemented EXE version information setting in build script (build/scripts/build_windows.py)
+- ✅ Added pefile dependency for version injection
+- Impact: MSI installer now properly detects and applies version updates
+- Status: Ready for Phase 5 release candidate builds
+
 **Application Status:**
 - Version: 1.0.0 (released Jan 28, 2026)
 - Phase 1-3: Complete (core features, testing, build system)

build/scripts/build_windows.py

@@ -145,6 +145,9 @@ class WindowsBuilder:
         if total_size > 0:
             print(f"   Total size: {total_size / 1024 / 1024:.1f} MB")
 
+        # Set executable version information (required for MSI updates)
+        self.set_exe_version(exe_path)
+
         # Generate SHA256 checksum
         self.generate_checksum(exe_path)
 
@@ -169,6 +172,52 @@ class WindowsBuilder:
         print(f"   File: {checksum_file}")
         print(f"   Hash: {checksum}")
 
+    def set_exe_version(self, exe_path: Path) -> None:
+        """Set executable file version for Windows.
+        
+        This is important for MSI updates: Windows Installer compares file versions
+        to determine if files should be updated during a major upgrade.
+        
+        Args:
+            exe_path: Path to the executable file
+        """
+        print("\n🏷️  Setting executable version information...")
+        
+        try:
+            import pefile
+        except ImportError:
+            print("⚠️  pefile not installed - skipping EXE version update")
+            print("   Note: Install with: pip install pefile")
+            print("   EXE version info will be blank (MSI updates may not work correctly)")
+            return
+        
+        try:
+            pe = pefile.PE(str(exe_path))
+            
+            # Parse version into 4-part format (Major, Minor, Build, Revision)
+            version_parts = self.version.split(".")
+            while len(version_parts) < 4:
+                version_parts.append("0")
+            
+            file_version = tuple(int(v) for v in version_parts[:4])
+            
+            # Set version resource if it exists
+            if hasattr(pe, "VS_FIXEDFILEINFO"):
+                pe.VS_FIXEDFILEINFO[0].FileVersionMS = (file_version[0] << 16) | file_version[1]
+                pe.VS_FIXEDFILEINFO[0].FileVersionLS = (file_version[2] << 16) | file_version[3]
+                pe.VS_FIXEDFILEINFO[0].ProductVersionMS = (file_version[0] << 16) | file_version[1]
+                pe.VS_FIXEDFILEINFO[0].ProductVersionLS = (file_version[2] << 16) | file_version[3]
+                
+                # Write modified PE back to file
+                pe.write(filename=str(exe_path))
+                print(f"✅ Version set to {self.version}")
+            else:
+                print("⚠️  No version resource found in EXE")
+                
+        except Exception as e:
+            print(f"⚠️  Could not set EXE version: {e}")
+            print("   MSI updates may not work correctly without file version info")
+
     def create_msi(self) -> bool:
         """Create MSI installer using WiX Toolset.
 

requirements-dev.txt

@@ -14,6 +14,7 @@ isort>=5.12.0
 
 # Building
 pyinstaller>=6.0.0
+pefile>=2023.2.7
 
 # Documentation
 sphinx>=7.0.0