TMD-MQTT/MQTT-Broker/MQTT-Broker.csproj

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <RootNamespace>MQTT_Broker</RootNamespace>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Server.Kestrel.Https" Version="2.2.0" />
    <PackageReference Include="MQTTnet.AspNetCore" Version="3.0.11" />
    <PackageReference Include="MQTTnet.Extensions.WebSocket4Net" Version="3.0.11" />
  </ItemGroup>
</Project>