diff --git a/appcast.xml b/appcast.xml
index 3de0c1a..8fb510e 100644
--- a/appcast.xml
+++ b/appcast.xml
@@ -11,7 +11,7 @@
       <pubDate>Tue, 28 Jul 2026 20:33:00 +0400</pubDate>
       <enclosure
           url="https://storage.yandexcloud.net/warcraft-client/moonwell_launcher_setup.exe"
-          sparkle:version="1.0.1"
+          sparkle:version="1.0.1+2"
           sparkle:shortVersionString="1.0.1"
           sparkle:os="windows"
           sparkle:dsaSignature="MD4CHQCdoCW5jNymVlRblQpqy8C+jw4W0rVFQX0Bk25PAh0Av2ZcFYwZFQBQlAstQXna/PsuMNWIzXF4jpDuSA=="
diff --git a/docs/launcher_self_update.md b/docs/launcher_self_update.md
index cabc0bd..98dcb5b 100644
--- a/docs/launcher_self_update.md
+++ b/docs/launcher_self_update.md
@@ -50,8 +50,11 @@ certificate would not establish trust on player machines.
 ## Version and AppCast Contract
 
 Increase the `X.Y.Z` version in `pubspec.yaml` for every launcher release. A
-build-number-only change such as `1.0.0+2` is not sufficient because WinSparkle
-compares the Windows product version. Pass the same `X.Y.Z` value to Inno Setup:
+build-number-only change such as `1.0.0+2` is not sufficient for a public
+release. Flutter writes the complete `X.Y.Z+N` value into the Windows
+`ProductVersion`; `sparkle:version` must match that complete value exactly.
+Use `sparkle:shortVersionString` for the human-readable `X.Y.Z` value. Pass
+`X.Y.Z` without the build suffix to Inno Setup:
 
 ```powershell
 ISCC.exe /DMyAppVersion=1.1.0 installer\moonwell_launcher.iss
@@ -75,7 +78,8 @@ Use a public AppCast with absolute URLs:
       <pubDate>Sun, 21 Jun 2026 12:00:00 +0400</pubDate>
       <enclosure
           url="https://storage.yandexcloud.net/warcraft-client/moonwell_launcher_setup.exe"
-          sparkle:version="1.1.0"
+          sparkle:version="1.1.0+3"
+          sparkle:shortVersionString="1.1.0"
           sparkle:os="windows"
           sparkle:dsaSignature="SIGNATURE_FROM_SIGN_UPDATE"
           length="ACTUAL_INSTALLER_SIZE_IN_BYTES"
diff --git a/docs/production_deploy.md b/docs/production_deploy.md
index 3558103..b7732b4 100644
--- a/docs/production_deploy.md
+++ b/docs/production_deploy.md
@@ -78,9 +78,11 @@ Increase both parts of the version in `pubspec.yaml`:
 version: 1.0.2+3
 ```
 
-`X.Y.Z` is the WinSparkle release version. `N` is the Flutter build number.
-Every production release must have an `X.Y.Z` value greater than the version
-currently published in AppCast.
+`X.Y.Z` is the public launcher version. `N` is the Flutter build number.
+Flutter places the complete `X.Y.Z+N` value in the Windows `ProductVersion`,
+so the script writes that same complete value to `sparkle:version` and writes
+`X.Y.Z` to `sparkle:shortVersionString`. Every production release must have an
+`X.Y.Z` value greater than the release currently published in AppCast.
 
 Run a dry run first:
 
diff --git a/tool/deploy_launcher.ps1 b/tool/deploy_launcher.ps1
index 75fece0..5d0a450 100644
--- a/tool/deploy_launcher.ps1
+++ b/tool/deploy_launcher.ps1
@@ -179,6 +179,7 @@ function Write-Appcast {
     param(
         [Parameter(Mandatory = $true)][string]$Path,
         [Parameter(Mandatory = $true)][string]$Version,
+        [Parameter(Mandatory = $true)][string]$BuildVersion,
         [Parameter(Mandatory = $true)][string]$Notes,
         [Parameter(Mandatory = $true)][string]$InstallerUrl,
         [Parameter(Mandatory = $true)][string]$Signature,
@@ -229,7 +230,7 @@ function Write-Appcast {
             'sparkle',
             'version',
             $script:SparkleNamespace,
-            $Version
+            $BuildVersion
         )
         $writer.WriteAttributeString(
             'sparkle',
@@ -469,9 +470,10 @@ try {
                 -UseBasicParsing `
                 -OutFile $publishedPath
             $publishedVersion = Get-AppcastVersion -Path $publishedPath
+            $publishedReleaseVersion = $publishedVersion.Split('+')[0]
             if (
                 -not [string]::IsNullOrWhiteSpace($publishedVersion) -and
-                [version]$version -le [version]$publishedVersion
+                [version]$version -le [version]$publishedReleaseVersion
             ) {
                 throw (
                     "Version $version is not newer than published version " +
@@ -573,6 +575,7 @@ try {
         '/' +
         $S3Key
     )
+    $appcastBuildVersion = "$version+$buildNumber"
     $appcastPath = if ($DryRun) {
         Join-Path $temporaryDirectory 'appcast.xml'
     }
@@ -583,6 +586,7 @@ try {
     Write-Appcast `
         -Path $appcastPath `
         -Version $version `
+        -BuildVersion $appcastBuildVersion `
         -Notes $ReleaseNotes `
         -InstallerUrl $installerUrl `
         -Signature $signature `
@@ -592,7 +596,7 @@ try {
         -LiteralPath $appcastPath `
         -Raw `
         -Encoding UTF8
-    if ((Get-AppcastVersion -Path $appcastPath) -ne $version) {
+    if ((Get-AppcastVersion -Path $appcastPath) -ne $appcastBuildVersion) {
         throw 'The generated AppCast contains the wrong version.'
     }
 
@@ -721,7 +725,7 @@ print("S3_CONTENT_LENGTH=" + str(response["ContentLength"]))
         $publishedEnclosure.GetAttribute(
             'version',
             $script:SparkleNamespace
-        ) -ne $version -or
+        ) -ne $appcastBuildVersion -or
         [long]$publishedEnclosure.length -ne $installer.Length -or
         $publishedEnclosure.url -ne $installerUrl
     ) {