I'm looking a documentation for building our custom Webpart using SharePoint 2013. We got a old document from Virtual campus using SharePoint 2007-2010, but I need something similar but for SharePoint 2013. We built a custom Webpart using SharePoint 2010 and we need to upgrade this Webpart for SharePoint 2013. The SharePoint server 2013 is a brand new server and has deployed PI Webpart solution 2013 SPx.
If you have some recommendations for updating our custom webpart, will be appreciated.