diff --git a/build-windows-5.10/Get-Mailcore2.ps1 b/build-windows-5.10/Get-Mailcore2.ps1
index 0efecb927..8b5429d8d 100644
--- a/build-windows-5.10/Get-Mailcore2.ps1
+++ b/build-windows-5.10/Get-Mailcore2.ps1
@@ -8,7 +8,7 @@ if (-Not $InstallPath) {
     $InstallPath = "$ProjectRoot\.build\install"
 }
 
-$PrebuiltMailcoreVersion = 4
+$PrebuiltMailcoreVersion = 5
 $PrebuiltMailcoreArchive = "mailcore2-all-$PrebuiltMailcoreVersion.zip"
 $PrebuiltMailcoreUrl = "https://spark-prebuilt-binaries.s3.amazonaws.com/$PrebuiltMailcoreArchive"