diff --git a/neo/neo.csproj b/neo/neo.csproj
index c9f7134030..556487c280 100644
--- a/neo/neo.csproj
+++ b/neo/neo.csproj
@@ -27,6 +27,7 @@
     <PackageReference Include="Microsoft.AspNetCore.Server.Kestrel" Version="2.2.0" />
     <PackageReference Include="Microsoft.AspNetCore.Server.Kestrel.Https" Version="2.2.0" />
     <PackageReference Include="Microsoft.AspNetCore.WebSockets" Version="2.2.1" />
+    <!-- Check https://github.com/neo-project/neo/pull/535 before upgrade this package -->
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.4" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="2.2.0" />
     <PackageReference Include="Neo.VM" Version="3.0.0-CI00035" />