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Migration to 3.x


I want to migrate from version v2.10.0.0 to v3.4.

But i can't find steps that i can follow in Docs.

Here is my understanding,it will help a lot if you can tell which is wrong:

Step1: download Groupdocs.viewer.dll and replace the old one.

Step2:replace the old apis with the new.(refer to the source code ,right?)

Is these two steps enough?

Also , is there some documents that can help me to know what functions in the old version are disabled in the new one,and what functions are new?

Here is another question.

My UAT environment and PROD environment share the same License.

I just want to do the migration in UAT environment to have a test.

Will it impact my PROD environment?


Hi xiaoyuwan,

Thanks for taking interest in Next Generation GroupDocs.Viewer for .NET API.

First of all, please note that the Next Generation API starting v3.0 is completely different from the older versions. The front end UI has been disintegrated from the API and only back-end document processing APIs are exposed in 3.x series. Therefore, just replacing the old DLL with new one will not work for you. We have also provided a migration article for the customers who are interested in Next Generation API.

Furthermore, we have also provided the open source front end UI applications in which Next Generation API is used for document processing. You can download any of our front end applications to evaluate and understand their working. These front end applications are also useful for the developer who want to develop their own applications. Listed below are the names and download links for front end applications:

To evaluate all the features of GroupDocs.Viewer back end API, we have also provided console example project in which all the features are implemented in the form of functions. You can check an evaluate all the features one by one. To download the example project follow below link

Next Generation GroupDocs.Viewer API covers all the features which were previously provided in the older versions along with some new features but the coding style and namespaces have been completely changed. To read about all the features in details, please see API’s documentation.

Finally, if you are running different applications in PROD and UAT environments then migration in any of them will not effect the other one and they will still be able to share the same license.

If you have any further questions, please let us know.

Warm Regards


Hi usman.aziz,

Thanks for your detailed introduction.

I have a question about displaying the pdfs.

The requirement is to display pdfs by [Stream] because we cannot get the original file path.

In v2.x , we accomplish this function as below in the .cs file:



In v3.x, i got code below from the samples on the page:


filePath: '...pdf',




1.Can i still use [Stream] in v3.0? Code is just the same as filePath?

2.If not , how to accomplish loading pdf by stream?

3.there are so many methods in the samples, can you please explain me how these functions cooperate with each other?

for example , if i want to display the pdf ,what method is needed?

and,which methods are needed expect for [showPrint:true] and[usePdfPrinting:true]?


Hi xiaoyuwan,

Thanks for raising your questions.

Yes, next generation GroupDocs.Viewer for .NET API supports rendering documents from streams. In our sample front end applications, loading files from stream method is not implemented with JavaScript parameter. However, this feature is implemented in the back end code of the viewer. You can check the source code of ASP.NET_MVC_Front_End
or ASP.NET_WebForm_Front_End in which stream functionality is handled using Dictionary<string, Stream> _streams object and you can customize the code according to your requirements. To read more about working with streams, please visit this link.

Secondly, in sample front end applications, an AJAX call is posted from jQuery to back end C# method “ViewDocument”. The back end method processes the request, renders the document into html/image and sends the response back to the calling jQuery. At the end, the document pages are displayed in the viewer. You can check the workflow and working of implemented methods by running sample front end applications.

If you have any further questions, please feel free to ask.

Warm Regards