---
title: "Updating Signer on Windows Server"
description: "How to update Signer on Windows Server with IIS: check the installed version, back up, replace the site binaries, confirm the new version and know how to roll back."
canonical: "https://docs.lacunasoftware.com/en-us/articles/signer/on-premises/windows/update"
locale: "en"
product: "Signer"
last_updated: "2026-10-22"
---

# Updating Signer on Windows Server

This page shows how to update an on-premises Signer instance installed on IIS following the
[Windows Server setup](https://docs.lacunasoftware.com/en-us/articles/signer/on-premises/windows).

## Before you update

1. Check the installed version. Open `https://<your-domain>/api/system/info` in the browser. The `productVersion`
   field shows the version.
1. Read the [changelog](https://docs.lacunasoftware.com/en-us/articles/signer/changelog) of every version between yours and the new one. Look for the versions
   marked as changing the database model.
1. If you are moving from 2.x to 3.x, also follow [Updating to 3.x](https://docs.lacunasoftware.com/en-us/articles/signer/on-premises/update-30). Version 3.0.0 requires
   the .NET 10.0 *Hosting Bundle*. Install it before you replace the binaries.
1. Update the staging environment first. Test sending and signing documents before you update production.
1. Pick a low-usage time. On the first startup, the application updates the database when the new version changes
   the model.

> **Warning**
>
> If you have more than one server, only one of them must update the database. Stop the other servers, update one
> server and wait for it to start. Then update the others. Alternatively, on every server but one, set
> `General:AutoUpdateDatabase` and `General:ProcessBackgroundJobs` to `false` in `appsettings.iis.json`.

## Backup

1. Stop the site in IIS Manager.
1. Back up the database in SQL Server.
1. Copy the site folder (for example, `C:\inetpub\Signer`). The copy includes `appsettings.iis.json`.

## Update

1. Download the new version package: `https://cdn.lacunasoftware.com/signer/signer-<version>.zip`. The links for each
   version are in the [changelog](https://docs.lacunasoftware.com/en-us/articles/signer/changelog).
1. Extract the package to the site folder and overwrite all files.
1. Make in `appsettings.iis.json` the changes the changelog asks for.
1. Start the site in IIS Manager.

> **Note**
>
> The package has no `appsettings.iis.json` file, so your configuration does not change. The package does have a
> `web.config`. If you changed `web.config` (for example, the IIS upload limit), apply the change again after you
> extract the package. See [Upload size limit](https://docs.lacunasoftware.com/en-us/articles/signer/on-premises/limite-de-upload).

## Check the update

1. Open `https://<your-domain>/api/system/info` and check that `productVersion` shows the new version.
1. Open the log file (set in `Serilog`, for example `C:\Logs\Signer.log`) and look for startup errors. The database
   update can take a few minutes.

If the site does not start and the log shows `PKI SDK License was not loaded successfully`, the application did not
load the PKI SDK license (missing, invalid or expired). Ask Lacuna for an updated license and set it in
`PkiSuite:SdkLicense`.

If IIS shows error `500.31` right after an update to 3.x, check that the .NET 10.0 *Hosting Bundle* is installed.

## If something goes wrong

If the new version has a problem, contact Lacuna support first. If you must go back to the previous version, follow
the [version rollback](https://docs.lacunasoftware.com/en-us/articles/signer/on-premises/rollback). To restore only the binaries, stop the site and restore the copy of
the site folder.

## See also

* [Windows Server setup](https://docs.lacunasoftware.com/en-us/articles/signer/on-premises/windows)
* [Version rollback](https://docs.lacunasoftware.com/en-us/articles/signer/on-premises/rollback)
* [Changelog](https://docs.lacunasoftware.com/en-us/articles/signer/changelog)