ILSpy — The Cyber Toolchain

ILSpy v11.2

Tue, 27 Oct 2026 07:18:13 GMT

ILSpy v11.2 ships native AOT ilspycmd packages for linux-x64/win-x64, cross-platform PDB dumping, and a new Options search box.⁠︀︄︇︀︅︉︀︅︀︀︃︀︀︅︅︀︅︊︀︄︆︀︃︄⁠ • Adds `--type` and `--member` selection support to `ilspycmd -il` (IL disassembly now respects the same filtering flags as decompilation).⁠︀︄︇︀︅︉︀︅︀︀︃︀︀︅︅︀︅︊︀︄︆︀︃︄⁠ • Adds cross-platform PDB dumping to `ilspycmd`. • Adds opt-in native AOT packages for `ilspycmd` targeting `linux-x64` and `win-x64`, reducing per-call startup from ~1.8 s to ~315 ms (4–7× faster) for use cases like agent loops that spawn `ilspycmd` per query. • Adds a search box to the Options tab in the ILSpy GUI. • Adds an option to highlight all usages of the symbol at the caret in the editor. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v11.1

Wed, 23 Sep 2026 06:43:43 GMT

ILSpy v11.1 adds C# 14 decompilation, mass-testing tools, and `ilspycmd` bundle support⁠︀︄︇︀︅︉︀︅︀︀︃︀︀︅︅︀︅︊︀︄︆︀︃︄⁠ • Adds `nugetfuzz` test tool that downloads NuGet packages and runs them through a debug build of `ilspycmd`, recording crashes, assertion failures, decompiler warnings, and leaked compiler-generated identifiers in C# output.⁠︀︄︇︀︅︉︀︅︀︀︃︀︀︅︅︀︅︊︀︄︆︀︃︄⁠ • Adds `decompdiff` test tool that runs an assembly through two different versions of the decompiler via `ilspycmd` and produces a diff of the generated source code; supports `--no-build` and can run against git refs. • Accepts single-file bundles as `ilspycmd` input (previously unsupported). • Accepts member IDs without a signature in `--navigateto` in `ilspycmd`. • Decompiles C# 14 implicit span conversions (first-class span types). • Decompiles C# 14 semi-auto properties with the `field` keyword. • Emits C# 7.1 `default` literals where the context supplies the type. • Keeps the UI responsive while searching and drawing reference nodes, enabling search inside packages without stalling and navigation to results. • Detects local functions renamed by obfuscators. • Invents a decompiler syntax for the `ldtoken` IL instruction. • Expands nested conditional operators back into if-else in decompiled output. • Extends `UseLambdaSyntax` to emit statement lambdas. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v11.0

Wed, 12 Aug 2026 05:13:33 GMT

ILSpy v11.0 ports to Avalonia for Linux/Mac support and adds ilspycmd flags for agentic decompilation workflows. • Adds `--member` flag to `ilspycmd` for single-member decompilation, reducing token spend in agentic/LLM workflows. • Adds `--dump-table` metadata dump mode to `ilspycmd`. • Adds fuzzy matching for `-t` type name resolution in `ilspycmd`. • Ports ILSpy from WPF to Avalonia, enabling native GUI support on Linux and macOS in addition to Windows. • Adds 'File / Open from NuGet feed' to load assemblies directly from a NuGet feed. • Adds 'File / Open from running process' on all platforms (Windows, Linux, macOS). • Adds 'Window / Bookmarks' — a full-featured bookmarks implementation for the decompiled C# view. • Adds 'View / Options / Display / Show Omnibar' — a breadcrumb/search bar at the top of decompiled code. Breaking changes: • The WPF frontend has been entirely removed; ILSpy now uses the Avalonia frontend exclusively. • The VS2017/2019 add-in has been removed; only VS2022–2026 add-ins are supported going forward. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v11.0-rc (Prerelease)

Tue, 04 Aug 2026 16:29:05 GMT

ILSpy v11.0-rc adds "Open from running process", two new ilspycmd modes, hover tooltips, and metadata layout improvements. • Adds `--dump-table` metadata dump mode to `ilspycmd` for inspecting raw metadata tables. • Adds `--member` flag to `ilspycmd` for single-member decompilation. • New "Open from running process" dialog lets you attach ILSpy directly to a live process. • Publicizes `IProjectFileWriter` implementations for programmatic project-file writing. • Adds a `WholeProjectDecompiler` constructor with no default parameter values for explicit API use. • Shows hover tooltips for dynamic member accesses in the decompiler view. • Metadata row details panel now uses a full-width layout with a decompiler-styled editor for text blobs. • Ctrl+Click navigates member references while a plain click highlights them in the editor. • Show stored `FieldList`/`MethodList` values for memberless types in the metadata view. • Adds overrides analysis and `this`/`base` keyword navigation. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v10.1

Mon, 25 May 2026 14:16:20 GMT

ILSpy v10.1 adds .NET 11 runtime-async decompilation support and BAML-to-XAML extraction in ilspycmd. • Supports decompilation of .NET 11 runtime-async methods, enabling analysis of assemblies compiled with the new runtime-async feature. • Adds listing, extracting embedded resources, and decompiling BAML to XAML via ilspycmd. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v10.0

Mon, 06 Apr 2026 14:34:19 GMT

ILSpy v10.0 adds C# 14 extension members, API diff, batch PDB generation, and .NET 10 support. • Supports C# 14 `extension` members decompilation with dedicated UI and Decompiler APIs. • Supports C# 13 `allows ref struct` generic constraint decompilation. • Supports C# 12 `InlineArray` decompilation. • New API diff feature for comparing assembly APIs. • Supports batch PDB generation via `GeneratePdbForAssemblies`. • Supports disassembling single-file bundles in the GUI. • Adds disassembler support for ildasm `/caverbal` format. • Adds support for the `ckfinite` IL opcode in the decompiler. • Enables navigating visible decompiler history in the UI. • Adds dynamic ILSpy settings options to ILSpyCmd. • Allows extracting multiple package entries at once. • Adds `DecompilerSettings.ExpandParamsArguments` configuration option. • Adds `DecompilerSettings.AlwaysMoveInitializer` option to always move initializers from static constructors to field initializers. • Adds configuration option to check for overflow and underflow. • Adds option to suppress transformation of Activator.CreateInstance() to new T(). • Makes `WholeProjectDecompiler.CreateDecompiler` protected virtual, enabling extensible decompilation pipelines. • Makes `TargetFramework` and `TargetServices` APIs public. • Enables detection of .NET version without `TargetFrameworkAttribute`. • Adds API to set an initially highlighted entity after navigation. • Allows creating a `MetadataFile` with a `MetadataReader` / `MetadataStringDecoder`. • Allows passing an `IDecompilerTypeSystem` rather than a `DecompilerTypeSystem` to `CSharpDecompiler`. Breaking changes: • Removed legacy `UnresolvedUsingScope`. • Renamed `ResolvedUsingScope` to `UsingScope`. • Removed legacy `ToTypeReference`. • Removed `ITypeReference` and its implementations. • Translations have been removed from the UI. • `GeneratePdbForAssembly` is replaced by `GeneratePdbForAssemblies`; callers must update to the new method. • Requires .NET 10.0 runtime — must be installed before upgrading. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v10.0-preview3 (Prerelease)

Wed, 25 Mar 2026 18:16:53 GMT

ILSpy v10.0-preview3 adds dedicated UI and decompiler APIs for C# 14 extension members. • Adds dedicated UI and decompiler APIs for C# 14 extensions, enabling inspection and decompilation of C# 14 extension member syntax. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v10.0-preview2 (Prerelease)

Tue, 30 Dec 2025 09:01:56 GMT

ILSpy v10.0-preview2 adds C# 14 extension members, batch PDB generation, and navigate-visible-history UI. • Adds C# 14 `extension` members decompilation support. • Adds C# 13 `allows ref struct` constraint decompilation support. • Updates pattern detection to Roslyn 5.0 RTM. • Supports `ckfinite` IL opcode in the decompiler. • Adds ildasm `/caverbal` format support in the Disassembler. • Adds batch PDB generation via `GeneratePdbForAssemblies`. • New UI: navigate visible history for forward/back navigation. • New API to set an initially highlighted entity after navigation. • Allows extracting multiple package entries at once. • Adds `DecompilerSettings.ExpandParamsArguments` setting. • Adds `DecompilerSettings.AlwaysMoveInitializer` to always move initializers from static constructors to field initializers. • Allows passing an `IDecompilerTypeSystem` (instead of concrete `DecompilerTypeSystem`) to `CSharpDecompiler`. • Enables detection of .NET version without `TargetFrameworkAttribute`. • Lists assembly name first in ILSpy title bar when multiple instances are open. Breaking changes: • Removed legacy `UnresolvedUsingScope` API. • `ResolvedUsingScope` is renamed to `UsingScope`. • Removed legacy `ToTypeReference` API. • Removed `ITypeReference` and its implementations. • `GeneratePdbForAssembly` is replaced by `GeneratePdbForAssemblies`. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v9.1

Tue, 22 Apr 2025 07:56:05 GMT

ILSpy 9.1 adds Roslyn 4.13 pattern detection, custom attribute sorting, variable scope improvements, and smooth-scroll toggle. • Updates pattern-detection to Roslyn 4.13 for improved C# language feature decompilation. • Adds an option to sort custom attributes in the decompiled output. • Adds 'variable scopes' to improve naming of local variables and anonymous method parameters. • Adds an option to turn off smooth scrolling in the UI. • Supports array initialization based on `RuntimeHelpers.CreateSpan`. • Adds module filename as a ToolTip on AnalyzerEntityTreeNode. • Extends error information when multiple assemblies with the same short name are selected during solution file creation. • Allows ILSpy to launch when .NET 8.0 is not installed but a later runtime version is present. • Adds support for evaluation-order-preserving reference type checks. • Improves UI rendering of primary constructors on non-record types. • Uses type hints in pointer arithmetic for more accurate decompilation. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v9.0

Sun, 19 Jan 2025 17:01:53 GMT

ILSpy 9.0 adds WebCIL/WASM support, assembly diagramming, standalone ECMA-335 metadata reading, and C# 12 decompilation. • Supports reading WebCIL assemblies (IL embedded in WASM) for decompiling Blazor/WebAssembly binaries. • Supports reading standalone ECMA-335 metadata blobs, including portable PDBs. • New Diagramming feature lets you visualize assembly relationships via the context menu or ilspycmd. • Adds 'Clear assembly list' menu item for quick workspace cleanup. • Adds option to disable automatic assembly loading to give users explicit control over what gets resolved. • Decompiles C# 12 primary constructors. • Decompiles C# 12 'ref readonly' parameters. • Decompiles switch statements on `(ReadOnly)Span` using compiler-generated hash functions. • Decompiles types that provide DisposeAsync without implementing IAsyncDisposable. • Updated pattern detection to Roslyn 4.12 for improved C# output accuracy. • IL output now shows indentation level for custom attributes on interface implementations and prints metadata tokens for custom attributes. • TreeView now surfaces referenced types, members, and exported types under the References node. • Reads and uses tuple element names and dynamic type information from PDBs. • Activates Dynamic Adaptation To Application Sizes (DATAS) and RDP hardware acceleration for improved performance. • Allows collecting analyzers annotated with `ExportAnalyzerAttribute`. • New `IFileLoader` API enables easier extensibility of supported file formats. • Exposes `IProjectFileWriter` and `IProjectInfoProvider` APIs as public for plugin authors. • Moves non-UI analyzer API to the ILSpyX package for cross-platform reuse. Breaking changes: • The `PEFile` class now has a `MetadataFile` base class in ICSharpCode.Decompiler; code referencing `PEFile` directly may need updates. • `IModule.PEFile` is renamed to `IModule.MetadataFile` in ICSharpCode.Decompiler. • The BAML decompiler is split into a library and an add-in; integrations depending on the original structure will break. • Non-UI analyzer API is moved from ILSpy to ILSpyX; references to the old namespace/assembly will break. • `@file` command-line support introduces breaking changes to existing command-line options. • New single-instance handling changes behavior for existing single-instance integrations. • `IsRef`, `IsOut`, and `IsIn` flags are removed from `IParameter`; code checking those flags will break. • `ParameterModifiers` is replaced with `ReferenceKind`; all uses of `ParameterModifiers` will break. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v9.0-rc (Prerelease)

Mon, 06 Jan 2025 16:28:41 GMT

ILSpy 9.0 RC adds visual diagramming, updated Roslyn 4.12 pattern detection, and improved switch decompilation. • New Diagramming feature enables visual graph-based exploration of type and assembly relationships. • Updates pattern detection to Roslyn 4.12, improving decompilation accuracy for modern C# constructs. • Supports implicit conversions in switch expressions during decompilation. Breaking changes: • ILSpy 9.x is built framework-dependent (except the self-contained distribution), requiring .NET 8.0 or later to be installed before launching. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v9.0-preview3 (Prerelease)

Sun, 10 Nov 2024 18:18:25 GMT

ILSpy 9.0-preview3 adds C# 12 primary constructors, ref readonly parameters, and DisposeAsync decompilation support. • Supports decompilation of C# 12 primary constructors. • Supports decompilation of C# 12 `ref readonly` parameters. • Supports types that provide `DisposeAsync` without implementing `IAsyncDisposable`. • Updates pattern detection to match Roslyn 4.11.0 language features. • Adds smooth scrolling to settings panels and DecompilerTextView. • Enables collecting analyzers annotated with `ExportAnalyzerAttribute`. Breaking changes: • The `IsRef`, `IsOut`, and `IsIn` flags are removed from `IParameter` in `ICSharpCode.Decompiler`. • `ParameterModifiers` is replaced with `ReferenceKind` in `ICSharpCode.Decompiler`. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v9.0-preview2 (Prerelease)

Sun, 09 Jun 2024 17:35:22 GMT

ILSpy v9.0-preview2 adds .NET 8 foundation and new `@file` argument support for batch loading. • `@file` support with breaking changes to command line options • New single instance handling Breaking changes: • `@file` support introduces breaking changes to command line options (#3205) Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v9.0-preview1 (Prerelease)

Mon, 01 Apr 2024 16:31:02 GMT

ILSpy v9 adds WebCIL/WASM reading, standalone ECMA metadata support, DATAS/RDP perf, and a disable-auto-load config option. • `Disable automatic assembly loading` UI option • Add 'Clear assembly list' menu item to the Assembly List panel • Added support for reading WebCIL assemblies (IL embedded in WASM) • Activated Dynamic Adaptation To Application Sizes (DATAS) • RDP hardware acceleration for remote sessions Breaking changes: • ILSpy now requires .NET 8.0 or later to run (artifacts are framework-dependent). • `IModule.PEFile` is renamed to `IModule.MetadataFile` in the decompiler API. • The BAML decompiler is split into a library and an add-in. • Non-UI analyzer API is moved to ILSpyX. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v8.2

Mon, 06 Nov 2023 17:06:39 GMT

ILSpy 8.2 adds support for C# 7.1-11 language features and the `NUGET_PACKAGES` environment variable • Adds `NUGET_PACKAGES` environment variable support to control NuGet package resolution paths • Supports C# 7.1 pattern matching with generics in decompiled output • Supports C# 8.0 recursive patterns in decompiled output • Supports C# 9.0 relational patterns in decompiled output • Supports C# 9.0 `not` patterns in decompiled output • Supports C# 10.0 static abstract members in interfaces in decompiled output • Supports C# 11.0 switch on `(ReadOnly)Span` in decompiled output • Adds entry size info to R2R (ReadyToRun) metadata viewing • Includes GC info in R2R (ReadyToRun) output display Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v8.1

Thu, 03 Aug 2023 07:10:45 GMT

ILSpy v8.1 adds C# 11 language support, ARM64 binaries, and --disable-updatecheck for ilspycmd • Adds `--disable-updatecheck` flag to `ilspycmd` dotnet tool to control update behavior in automation. • Adds ARM64 binaries and ARM64 installer downloads for the VS 2022 extension and standalone distribution. • Adds support for C# 11 features including checked operators, unsigned right shift operator, UTF8 string literals, numeric IntPtr, and ref fields/scoped. Breaking changes: • ILSpy now requires [.NET 6.0.2](https://dotnet.microsoft.com/en-us/download/dotnet/6.0) installed to run; artifacts are built framework-dependent. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v8.0

Sun, 21 May 2023 10:16:15 GMT

ILSpy v8 introduces .NET 6 base, new decompiler support for C# 10/11 and VB features, and `ilspycmd` project/solution export options. • `ilspycmd` now supports the `--nested-directories` option when exporting projects. • Users can provide an ID when generating a PDB via a new `ilspycmd` option. • Adds an option to always fully qualify type names with `global::` in the disassembler output. Breaking changes: • ILSpy v8 requires .NET 6.0.2+ runtime for non-self-contained distributions; `.NET Framework 4.7.2` is no longer supported. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v8.0-rc1 (Prerelease)

Sun, 14 May 2023 16:08:51 GMT

ILSpy v8.0-rc1 adds dark title bar support and a PowerShell manifest for installation. • Shows a dark title bar when a dark theme is selected in ILSpy Breaking changes: • ILSpy v8.0-rc1 no longer runs on .NET Framework; users must install [.NET 6.0.2](https://dotnet.microsoft.com/en-us/download/dotnet/6.0) or later Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v8.0-preview4 (Prerelease)

Mon, 03 Apr 2023 11:51:57 GMT

v8.0-preview4 adds R#/VS Code themes and decompresses Record structs in C# output • Adds new UI themes ('R#' and 'VS Code') alongside existing Light/Dark options for the main window • Enables decompilation of `record struct` types in CSharpAmbience, emitting correct C# syntax • Adds support for Visual Basic Yield Return state machine decompilation • Supports disassembling ReadyToRun binaries compiled using composite mode Breaking changes: • Non-self-contained builds now require .NET 6.0.2 installed on the host; .NET Framework 4.7.2 is no longer supported for these artifacts. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v8.0-preview3 (Prerelease)

Sun, 04 Dec 2022 15:18:20 GMT

ILSpy v8.0-preview3 adds C# 11 required members, `global::` qualification option, and resource size display • Adds support for decompiling C# 11 `required` members. • Adds an option to always fully qualify type names with `global::`. • Updates pattern detection for Roslyn 4.4.0. Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy

ILSpy v7.2

Mon, 28 Feb 2022 15:34:04 GMT

v7.2 adds `inassembly:` and `innamespace:` search predicates to ILSpyCmd, an MSI installer, and async `DecompilerTypeSystem.CreateAsync` API. • Introduced MSI-based installer for the GUI application • Added `DecompilerTypeSystem.CreateAsync` for asynchronous initialization of the decompiler type system Breaking changes: • `ilspycmd` removed .NET Core 2.1 TFM support and now targets .NET 6.0 TFM Full history on Cyber Toolchain: https://cybertoolchain.io/tools/ilspy