diff --git a/Rnwood.Smtp4dev/Rnwood.Smtp4dev.csproj b/Rnwood.Smtp4dev/Rnwood.Smtp4dev.csproj
index 1e42af762..802688049 100644
--- a/Rnwood.Smtp4dev/Rnwood.Smtp4dev.csproj
+++ b/Rnwood.Smtp4dev/Rnwood.Smtp4dev.csproj
@@ -35,7 +35,7 @@
 		</PackageReference>
 		<PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="5.0.8" />
 		<PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="5.0.8" />
-		<PackageReference Include="MimeKit" Version="2.15.1" />
+		<PackageReference Include="MimeKit" Version="3.4.0" />
 		<PackageReference Include="Mono.Options" Version="6.12.0.148" />
 		<PackageReference Include="Rnwood.LumiSoft.Net" Version="1.0.0" />
 		<PackageReference Include="Rnwood.SmtpServer" Version="3.1.0-ci0648" />