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Dynamsoft improves DWT constantly through one major version and 2 to 4 minor versions each year. The recommendation for our customers is to always keep your application up-to-date with our latest release. In this section, we’ll talk about how to upgrade your application.

The following three steps are required to upgrade your application to use a newer version of DWT . Two of the steps would be done by the application developer on the server-side. The 3rd step would be done by users or system administrators on the client side.

  1. Update the server-side resources for DWT
  2. Replace your old product key with the newer one
  3. Ensure client machines have uninstalled the old version of the service in preparation to install the newer version

Update the resources files

Read more about resources files.

Regular Web application

Uninstall the old version

  • Windows: Search Dynamic Web TWAIN in Control Panel -> Programs and Features , and remove all the relevant components there.

  • macOS: Execute Applications > Dynamsoft > Dynamic Web TWAIN SDK {Version Number} > Uninstall.pkg

Install the new version

You can use the official installer to install the new verion.

Download SDK

Replace the resources files

If you haven’t renamed the official folder, the resources files should reside in a folder named “Resources”. In this step, copy the new resources files and replace the old ones. The new files are typically found in the following location after the installation

  • Windows: C:\Program Files (x86)\Dynamsoft\Dynamic Web TWAIN SDK {Version Number}\
  • macOS: Applications > Dynamsoft > Dynamic Web TWAIN SDK {Version Number}

Applications that make use of the dwt package

If your application uses a framework or library like Angular , React , Vue , etc., the upgrade is easier as you just need to install the new version to replace the old one. For example

npm install dwt


yarn add dwt

You may want to update the types definition as well

npm install @types/dwt


yarn add @types/dwt

Update the Product Key

The Product Key needs to be updated when your current license is no longer valid (expired, for example) or when you upgrade across major versions. The Product Key is set using the global API Dynamsoft.WebTwainEnv.ProductKey and the change is only effective before creating WebTwain instances.

In most cases, you can just make the change in the file dynamsoft.webtwain.config.js .

// If you have multiple license keys, just separate them with semicolons.
Dynamsoft.WebTwainEnv.ProductKey = 't0076lQAAAGNcO61He******; t0076lQAAAGNcO61He******';

If it is set elsewhere, you need to find it and replace it. For example, if you are making use of the dwt package ( dynamsoft.webtwain.min.js or dynamsoft.webtwain.min.mjs ), the file dynamsoft.webtwain.config.js doesn’t exist and you should already have the above line of code in your own JavaScript where you can update the license when needed.

Update DWT on the client-side

Service mode

Starting in version 16.*, DWT is designed to be backward compatible (unfortunately, just as far back as 16.0). The compatibility is done in two ways

  • For minor versions like 16.1 to 16.2, if the newer version of DWT has been installed on a desktop, websites utilizing both the newer version and the older version can work without reinstallation of DWT
  • For major versions like 16.* to 17.*, the newer version will be installed to a different directory which can coexist with the older version. The user can choose to uninstall the old version if necessary

That means, once you, as the maintainer, have finished upgrading your application to a newer DWT on the server side, the clients could face one of two situations

  • If the clients have installed the same or even newer minor version of DWT themselves (probably from another application that uses DWT ), they don’t need to do anything;
  • If the clients never installed DWT or have an older version or a different new major version of it, they will be required to do a reinstallation of DWT . The process is described here.

WASM mode

By comparison, if DWT runs only in the WASM mode, the clients don’t need to install anything themselves as the WASM browsers will take care of the upgrade process. What the clients may encounter is a slower-than-usual page load when they visit the application for the first time after the upgrade.

Once upgraded, the old WASM files will continue to exist in the browser as cached data until it’s purged by the browser or by the user.

Other Topics

Expand your application to mobile platforms

If you are upgrading to version 16 for mobile functionality (basically, DWT in wasm mode), there are some considerations to be made. As mobile support is one of the newest offerings from Dynamsoft, not all of the old DWT features are fully available at present. That said, we are constantly working on increasing the supported mobile feature set, so we recommend reviewing our release notes, and if you have any questions, contact Dynamsoft Support.

As an example for how some existing DWT features will work on mobile platforms, see below:


This will become either capturing from mobile cameras or capturing from a Remote Windows machine in the LAN.


This will be either loading or capturing.


This will become an in-browser download operation as mentioned here.


Similar to existing desktop functionality but the performance is not as good.


Similar to existing desktop browser functionality but is limited to only one API HTTPUpload() .


Identical to current desktop browser functionality.

Barcode reading

Identical to current desktop browser functionality.

PDF Handling

Similar to current desktop browser functionality but the rasterizing feature depends on embeded fonts in the PDF file whereas the on desktop, the system fonts can also be used.


Client-side support is to be added in a later version.

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