Npgsql 4.0.10 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The following versions: 3.2, 3.0 and 2.2 are the most frequently downloaded ones by the program users.
This free program is an intellectual property of The Npgsql Development Team. You can launch this free PC software on Windows XP/Vista/7/8/10 32-bit. Npgsql lies within Development Tools, more precisely IDE. We recommend checking the downloaded files with any free antivirus.
From the developer:
Npgsql is an open source ADO.NET Data Provider for PostgreSQL, it allows programs written in C#, Visual Basic, F# to access the PostgreSQL database server. It allows any program developed for .NET framework to access database server. It is implemented in 100% C# code. This package works with PostgreSQL 9.x and above.
You may want to check out more software, such as Erlang, jEdit or Mono for Windows, which might be related to Npgsql.