Moving from AutoMapper 14¶

ForkForward.Mapper is AutoMapper 14.0.0 under a new name. The types, their members and the behaviour are the same; what changes is where they live.

Two steps¶

1. Package. Remove the AutoMapper package reference and add ForkForward.Mapper:

dotnet remove package AutoMapper
dotnet add package ForkForward.Mapper

If the project also references AutoMapper.Extensions.Microsoft.DependencyInjection, remove it too: AddAutoMapper is part of ForkForward.Mapper.

1. Namespaces. Replace AutoMapper with ForkForward.Mapper in using directives, including the sub-namespaces:

A global using (<Using Include="ForkForward.Mapper" /> in the project file) does it once for a whole project. For a solution, a search and replace of using AutoMapper with using ForkForward.Mapper is safe: no other identifier starts that way.

That is all. The code compiles and behaves as it did with AutoMapper 14.0.0.

What stays as it was¶

• Type names. IMapper, MapperConfiguration, Profile, AutoMapperMappingException, AutoMapperConfigurationException, AutoMapAttribute, AddAutoMapper and every other type and member keep their names, including the ones that carry the old project's name.
• Behaviour. Conventions, configuration, validation, projection: unchanged. The only difference in behaviour is a security fix: a source graph nested deeper than the thread's stack allows now ends in an AutoMapperMappingException instead of a process crash (CVE-2026-32933).
• Documentation. These pages are AutoMapper's, with the namespace updated.

What else changes¶

• Assembly identity. The assembly is ForkForward.Mapper.dll, signed with the fork's own key (public key token d1f0d2ab1c32618c). A library compiled against AutoMapper.dll does not load against this assembly; it has to be recompiled against ForkForward.Mapper. Assembly binding redirects cannot bridge the two, as the names differ.
• Both packages at once. AutoMapper and ForkForward.Mapper can be referenced in the same project without a conflict, since nothing overlaps, but a type from one is not the type from the other: an IMapper registered by AutoMapper does not satisfy a constructor that asks for ForkForward.Mapper.IMapper. Move a project as a whole.
• Version numbers continue from 14: ForkForward.Mapper 14.1.0 is the first stable release. The previews 14.1.0-preview.2 and 14.1.0-preview.3 still used the AutoMapper names.

Moving from AutoMapper 15 or later¶

AutoMapper 15 and later are under a different licence and were never part of this fork; their new features are not here. Code written for 14 that was later moved to 15 may use API that 14 does not have; the AutoMapper upgrade guides list what 15 added. Everything described on these pages is available.