Multron Updater

Multron Updater keeps a Windows program up to date straight from a GitHub repository. It watches a file or folder in a repo, and when it changes it downloads the new version (or builds it from source on this computer), closes the running program, replaces the files and starts the program again — automatically, from the system tray.

Built with C# / WPF on .NET 8.

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Features

• Multiple targets – add as many repo → program pairs as you like, each with its own settings. Enable, duplicate or remove them from the list.
• GitHub as the update source – pick any owner, repository, branch and path (a single file or a whole folder).
• Local repository folder (no internet) – update from a copy of the repository on disk (a clone, a USB drive, a network share) with the same safe install flow.
• Build from source (optional) – keep the source in a folder of its own, run your own build commands (cmd, Windows PowerShell or PowerShell 7) with the compilers on this computer and install the build output. Templates for .NET, MSBuild, Node.js, PyInstaller, Rust, Go and CMake, project detection, environment variables, a time limit and a build log. A failed build never touches the installed program.
• Versioned program names – write * in place of the version (ZapZap-*-windows-x86_64.exe): the running version is closed, the new release keeps its own name and the previous exe is removed.
• Pick instead of typing – fill in the release file and the program from the latest release's file list, from the running programs or with Browse...; the version in the name becomes * automatically.
• After-update actions per target – start the program again and/or refresh the active Microsoft Edge tab (F5).
• Light and dark theme – follows the Windows setting, or always light or dark, title bar included.
• Windows and console programs – start arguments, and for console apps: show the window, keep it open after exit, or run hidden with the output written to a log file. Console apps are closed with Ctrl+C before an update.
• Multron server options (for Multron developers) – hidden until General → Multron developers → Show Multron server options is turned on; the dashboard address and scan wait time can be set once there for every target:
• Multron server maintenance – for a Multron / VirusKov cloud scan server target, the server is switched to its "Updating server" maintenance mode through its local dashboard before it is closed: clients are told the server is being updated and scans in progress finish first. The updated server starts with scans open again.
• Multron server signature reload – when an update changes no program files (.exe / .dll), the files are replaced while the server keeps running and its signatures are reloaded through its dashboard instead of restarting it. If a file is held open by the server, it is closed and started as usual.
• Multron server seamless update – the server is not closed for the update. Files it holds open (its exe) are renamed to *.old-<time>, the new files are put in place and the new version is started with --handoff next to the running server. The running server keeps scanning in its "Getting updated" mode while the new one loads its engine; then it finishes the scans in progress (up to the "wait up to … s for scans" setting), hands its ports over and exits, and the new version is scanning again within about a second. If the new version does not take over (it crashed, or did not load within ServerSeamlessMinutes, 20 by default), the previous files are put back and the running server stays as it was. A server too old for it is updated the usual way once; the renamed *.old-* files are deleted after the switch (or on the next update).
• Paste-a-link setup – paste a GitHub link and the fields fill themselves in.
• Safe update flow – download → verify → close the program → replace files → restart. If replacing fails, the previous version is restored automatically.
• Only changed files are downloaded – local files are compared with GitHub's blob hashes (the same hash git uses).
• Automatic updates (optional) – turn it on with one switch and choose how often to check (in minutes).
• Runs in the background – closing the window keeps it running in the system tray.
• Download animation – a popup slides in at the bottom-right, the taskbar button shows a progress bar and the tray icon spins while an update downloads.
• Log system – color-coded log levels (Info / Success / Warning / Error) with filtering and search, also written to a log file.
• Backups – replaced files from the last 3 updates are kept.
• Private repositories – optional personal access token, stored encrypted (Windows DPAPI) for the current user.
• Start with Windows – registered as a logon task, so it starts without a UAC prompt.
• Auto-saving settings – every change is saved as you type.
• Updates itself – every push to main builds a new release, and Multron Updater installs it and restarts.

Requirements

• Windows 10 / 11 (x64)
• .NET 8 Desktop Runtime
• Administrator rights (the app asks for them on start, so it can close and replace programs that run elevated)

Getting started

1. Download MultronUpdater.exe from the latest release and run it.
2. In the Targets tab, select a target (or click + Add) and give it a name.
3. GitHub source – paste a link such as https://github.com/user/repo/blob/main/bin/Release/App.exe and click Fill from link, or enter Owner, Repository, Branch and Path in repository by hand.
4. Program on this computer – choose the target folder and, optionally, the .exe that should be closed while the files are replaced (Running... picks it from the running programs). To compile the program yourself, turn on Build from source and enter the build commands.
5. After updating – choose whether to start the program again and/or refresh the active Edge tab.
6. Click Check this target to run the first update. Repeat for more targets.
7. In the General tab, turn on Update automatically to keep every enabled target updated in the background.

Update source

Each target chooses where updates come from (GitHub source → Update source):

Option	What it does
Repository files + releases (default)	Files under Path in repository are kept in sync with the branch, so a push is seen right away. New releases install the files the repository does not have; a file that exists in both is taken from the repository.
Repository files only	Raw files from the branch. Each file is checked with its git hash; if a <file>.sha256 sits next to it in the repository, the SHA-256 is verified too.
Releases only	Installs the file(s) of the latest GitHub release, verified with the SHA-256 GitHub publishes for every asset.
Local repository folder (no internet)	Reads Path in repository from a copy of the repository on disk instead of GitHub. Nothing is downloaded and owner, repository, branch and token are not used.

Local repository folder (no internet)

For a computer without internet access (for example a Multron / VirusKov scan server), choose Local repository folder (no internet) and pick the root of the repository copy, e.g. C:\Users\me\GitHub\HydraDragonAntivirus, E:\HydraDragonAntivirus on a USB drive or \\MAINPC\share\HydraDragonAntivirus. Path in repository is read from that folder (a file or a folder; empty = the whole folder), so OpenMalwareScannerPortable keeps a Multron server install in sync.

• Files are compared with SHA-256; only new or changed files are copied. A file you changed in the target folder is put back. When the copy's names, sizes and times have not changed since the last check, nothing is hashed, so frequent automatic checks stay cheap.
• The changed files are first copied into a staging folder and checked again, so a file that changes in the repository copy while it is being copied is not installed. A <file>.sha256 next to a file in the copy is verified, and Git LFS pointers (a clone without git lfs pull) are refused.
• .git folders are skipped. Nothing is ever deleted from the target folder.
• Everything else is the same as for GitHub updates: Update only the checked files and file groups, Multron server maintenance and signature reload, closing and restarting the program, backups and automatic rollback.
• If the folder is missing (the USB drive or share is not connected), the check fails with that message and the installed files are left alone.

Release file(s) to install takes a file name, wildcards (MyApp-*-win64.zip) or several names separated by ;. When it is empty, the name of the program (or of the file in Path in repository) is used. A single .exe asset is installed under the program's name, and .zip assets are extracted into the target folder (a single top folder inside the zip is skipped). Show latest release lists the files of the latest release and marks the ones that match; Use this file fills in the release file (and the program, for an .exe) with * in place of the version.

Checking for a new commit or a new release tag does not use the GitHub API, so frequent checks do not run into the 60 requests/hour limit; the API is only called when something actually changed.

Console programs

In Program on this computer, choose Console app (it is detected automatically when you pick the .exe with Browse...) and, optionally, Start arguments such as --port 8080 --silent. Then choose how the console window behaves:

Option	What happens
Show the console window	The program opens in its own console window.
Show it and keep it open after the program exits	Runs inside cmd /k, so the window stays open to read errors.
Run hidden in the background	No window; output and errors go to %AppData%\MultronUpdater\console-logs\<target>.log (Open console log).

Before replacing files, Multron Updater sends Ctrl+C so the program can shut down cleanly and terminates it only if it is still running after 5 seconds. Use Start now to try the settings without waiting for an update.

File groups

Turn on Update only the checked files, in groups to pick exactly which files are updated:

• Load from GitHub lists the files under the path and marks them: yellow • changed, green + new, grey ✓ up to date, red − not found on GitHub.
• Drag files or folders from File Explorer onto a group (or use Add files...). They must be inside the target folder. Dropping a file that is already listed onto a group moves it there.
• Create groups with + New group, rename them by clicking the name, and drag files between groups (or right-click a file → Move to group).
• Each group has its own Enabled, Restart the program and Refresh Edge (F5) options. A group's actions run only when one of its files changed.

Refreshing Microsoft Edge

With Refresh the active Microsoft Edge tab (F5) enabled, Multron Updater brings the most recently used Edge window to the front after the update, presses F5 and then gives focus back to the window you were using. This is handy when the target is a web page or a local web app.

File or folder?

Path in repository	What is synced
bin/Release/App.exe	Only that file
bin/Release	Every file inside the folder (sub-folders included)

Tip: For .NET apps that are not published as a single file, the .exe is only a small launcher and the real code lives in the .dll next to it. Use the folder path in that case.

Versioned program names (*)

Some programs put the version in the file name (ZapZap-7.5.1-windows-x86_64.exe). Write * in place of the version in Program to close (ZapZap-*-windows-x86_64.exe): every running copy that matches is closed, the new release is installed under its own name, the previous version's exe is removed (and kept in the backup) and the new one is started.

You do not have to type it: Show latest release lists the release files with a Use this file button, Running... lists the running programs (and everything running from the target folder, such as a hidden server), and Browse... picks a file. All three fill in the fields with * in place of the version.

Build from source (optional)

Turn on Build the program from the downloaded source before installing it to compile the program on this computer instead of downloading a ready-made exe:

1. The repository (leave Path in repository empty for the whole repository) or the local repository folder is kept in a source folder (default %AppData%\MultronUpdater\sources\<target id>).
2. Your build commands run there with the compilers installed on this computer, in Command Prompt, Windows PowerShell or PowerShell 7. All lines run in one shell, so cd, set and variables carry over. Stop at the first command that fails checks the exit code after every complete command.
3. The files of the output folder that differ from the installed ones are installed into the target folder with the usual flow (close, back up, replace, restart).

A failed or timed-out build never touches the installed program; automatic checks do not build the same failing version again (a manual check or a new commit does). Templates are included for .NET, MSBuild, Node.js, PyInstaller, Rust, Go, CMake and repository build scripts, and Detect picks one from the files in the source folder. The commands can use %MU_SOURCE%, %MU_OUTPUT%, %MU_TARGET%, %MU_VERSION%, %MU_EXE% and %MU_TARGET_NAME% ($env:MU_SOURCE in PowerShell) plus your own environment variables. Build and install now builds even when the source has not changed.

Theme

General → Application → Theme: follow the Windows setting, or always light or dark.

Multron server options (developers)

The Multron server options (maintenance mode, signature reload, seamless update) are hidden unless General → Multron developers → Show Multron server options is on. The server dashboard address and the scan wait time set there are used by every target that keeps Use the global server settings.

How it works

1. Asks GitHub for the latest commit of the branch. This request uses an ETag, so when nothing has changed it does not count against GitHub's rate limit.
2. If the commit changed, reads the file list and compares each file with the local copy.
3. Downloads the changed files (pinned to the exact commit) and verifies their hashes.
4. With Build from source on: puts the files into the source folder, runs the build commands and takes the changed files of the output folder. A failed build stops here.
5. Closes the program (gracefully first, forcefully after 5 seconds; with a * name, every matching copy).
6. Backs up and replaces the files, then runs the after-update actions (restart the program, refresh Edge).

Targets are checked one after another.

Where things are stored

What	Location
Settings	%AppData%\MultronUpdater\settings.json
Log file	%AppData%\MultronUpdater\log.txt
Backups	%AppData%\MultronUpdater\backups\<target id>\
Console output (hidden console apps)	%AppData%\MultronUpdater\console-logs\
Source folders (build from source)	%AppData%\MultronUpdater\sources\<target id>\
Build logs	%AppData%\MultronUpdater\build-logs\

GitHub rate limit

Without a token GitHub allows 60 API requests per hour. Unchanged checks are free (HTTP 304), so a 5-minute interval works fine. If you hit the limit, or the repository is private, add a personal access token (read-only Contents permission is enough).

Updating Multron Updater itself

1. A push to the main branch starts the Build and release GitHub Actions workflow (.github/workflows/release.yml). Pushes that only change *.md, LICENSE or .gitignore are skipped.
2. The workflow builds the single-file exe and publishes it as a release named v<major>.<minor>.<run number>. Major and minor come from <Version> in MultronUpdater.csproj, so change it there to start a new series (e.g. 1.2.0).
3. Multron Updater checks the latest release 20 seconds after it starts and then every 3 hours (or on General → Check for updates). When a newer version exists it downloads it, checks its size and SHA-256, swaps its own exe and restarts in the same state (window open or in the tray).

Turn off Update Multron Updater automatically in the General tab to only get a notification and install the update with the Install button. Development builds (running from bin\) never update themselves.

Building from source

Requires the .NET 8 SDK (or newer).

build.bat

build.bat publishes a single-file exe to publish\MultronUpdater.exe. If Multron Updater is running, it closes it first (it may ask for administrator permission).

Or manually:

dotnet publish -c Release -o publish

Do not publish into a folder that contains the project folder — the SDK then excludes the source files from compilation and produces a broken exe.

Limitations

• Files deleted from the repository are not deleted locally (in the target folder or the build source folder).
• Building uses the compilers installed on this computer; Multron Updater does not install them.
• Files stored with Git LFS are not supported.
• Very large repositories (100,000+ files) may return a truncated file list from GitHub.