packages.config reference

The packages.config file is used in some project types to maintain the list of packages referenced by the project. This allows NuGet to easily restore the project's dependencies when the project is to be transported to a different machine, such as a build server, without all those packages.

If used, packages.config must be located in a project root. It's automatically created when the first NuGet operation is run, but can also be created manually before running any commands such as nuget restore.

Projects that use PackageReference do not use packages.config.

Schema

The schema is simple: following the standard XML header is a single <packages> node that contains one or more <package> elements, one for each reference. Each <package> element can have the following attributes:

Attribute	Required	Description
id	Yes	The identifier of the package, such as Newtonsoft.json or Microsoft.AspNet.Mvc.
version	Yes	The exact version of the package to install, such as 3.1.1 or 4.2.5.11-beta. A version string must have at least three numbers; a fourth is optional, as is a pre-release suffix. Ranges are not allowed.
targetFramework	No	The target framework moniker (TFM) to apply when installing the package. This is initially set to the project's target when a package is installed. As a result, different <package> elements can have different TFMs. For example, if you create a project targeting .NET 4.5.2, packages installed at that point will use the TFM of net452. If you ;later retarget the project to .NET 4.6 and add more packages, those will use TFM of net46. A mismatch between the project's target and targetFramework attributes will generate warnings, in which case you can reinstall the affected packages.
allowedVersions	No	A range of allowed versions for this package applied during package update (see Constraints on upgrade versions. It does not affect what package is installed during an install or restore operation. See Package versioning for syntax. The PackageManager UI also disables all versions outside the allowed range.
developmentDependency	No	If the consuming project itself creates a NuGet package, setting this to true for a dependency prevents that package from being included when the consuming package is created. The default is false.

Examples

The following packages.config refers to two dependencies:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="jQuery" version="3.1.1" targetFramework="net46" />
  <package id="NLog" version="4.3.10" targetFramework="net46" />
</packages>

The following packages.config refers to nine packages, but Microsoft.Net.Compilers will not be included when building the consuming package because of the developmentDependency attribute. The reference to Newtonsoft.Json also restricts updates to 8.x and 9.x versions only.

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" version="1.0.0" targetFramework="net46" />
  <package id="Microsoft.Net.Compilers" version="1.0.0" targetFramework="net46" developmentDependency="true" />
  <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net46" />
  <package id="Microsoft.Web.Xdt" version="2.1.1" targetFramework="net46" />
  <package id="Newtonsoft.Json" version="8.0.3" allowedVersions="[8,10)" targetFramework="net46" />
  <package id="NuGet.Core" version="2.11.1" targetFramework="net46" />
  <package id="NuGet.Server" version="2.11.2" targetFramework="net46" />
  <package id="RouteMagic" version="1.3" targetFramework="net46" />
  <package id="WebActivatorEx" version="2.1.0" targetFramework="net46" />
</packages>