Hello Gaurika,

Thank you for contacting Infragistics!

First there are some things you should be aware of when upgrading. The Ultra/classic controls were retired after v11.1 and will have to be replaced if you are using any. The following blog goes over what controls were retired and what they were replaced with:

http://www.infragistics.com/community/blogs/taz_abdeali/archive/2011/11/17/asp-net-product-changes-in-2011-volume-2.aspx

As you not you are using CLR 2, As of the v12.2 release the product no longer supports or ships the CLR 2.0 assemblies, you can see the following blog for further information:

http://www.infragistics.com/community/blogs/jason_beres/archive/2012/05/29/updated-support-for-clr-versions-and-visual-studio-versions.aspx

The version utility will only update the assembly references for the controls that are a part of the product after the v11.2 release. Any old assembly references would have to be replaced/removed manually.

If you are using the ultra/classic controls which have been retired you will have to replace them manually with the aikido/ajax controls mentioned in the first blog.

You can go to the following links to see samples and documentation of these controls:
http://www.infragistics.com/samples/aspnet/

http://help.infragistics.com/doc/ASPNET/2012.2/CLR4.0/?page=Web_Controls.html

An alternative to this is to instead upgrade to our Ignite UI jQuery controls:
http://www.igniteui.com/help/
http://help.infragistics.com/jQuery/2015.1/

http://www.igniteui.com/

The decision on which to use would be a personal preference depending on what you like to use and how familiar you are with each platform ASP.NET or jQuery.

How to go about upgrading would depend on how many pages/controls you have to convert as well as how much time and resources you have to devote to this.

Please let me know if you have any further questions concerning this matter.