Most of us got this question .. what will happen to the custom web parts and customization we developed for Sharepoint 2007 ? .. will it work under Sharepoint 2010 or we have to reinvest in modifying them, fortunately i got these information from Microsoft :)

Custom code written for the 2007 version of SharePoint will work on a 2010 installation without requiring the customizations to be re-written:

·         The underlying Web Part model has not changed going from the MOSS 2007 version to SharePoint 2010

·         Microsoft added new and exciting options around the UI of SharePoint, using AJAX and Silverlight technologies, but these aren’t a pre-requisite and customers can choose when and how to use these options

·         Custom Web Parts and code written for the 2007 environment will run on a 2010 installation without any re-writing of code

·         As is the case for every production environment, Microsoft highly recommends thoroughly testing customized applications and Web Parts before deploying them to an upgraded environment

·         Microsoft has invested in backward compatibility so that custom Web Parts and code written for the 2007 environment will run on a 2010 installation without any re-writing of code

·          In addition, the SharePoint 2010 version supports APIs from the 2003 and 2007 versions in the sense that even APIs that have been deprecated, i.e. will not be invested in moving forward, will work with a SharePoint 2010 installation