There are a lot of differences between CRM versions CRM 4 and CRM 2011. It can take you a while to get use to the changes but after an initial period of confusion I think you will find the changes have dramatically improved developing CRM extensions.

Javascript changes were the most tricky to get my head round but like many of the other changes it has in the long run made writing Javascript easier and more logical.

The biggets improvement is Microsoft getting rid of the CRM variables, they are a complete pain and means you have to spend hours converting everything. I also think the solutions concept is brilliant.

I haven’t mentioned the new functionality but focused on what has changed in simliar functionality. The new functionality is

Webresouces,OData, WCF instead of webservices, online version allow sandboxed plugins, SSRS reporting using FetchXML, Sharepoint intergration

Synatx Difference between CRM4.0 and CRM2011

Below our some links to the syntax differences between CRM 4 and CRM 2011 for data types, plugins, javascript and workflows

Data Type Changes:

Plug-in Changes:

Java Script Changes:

This link shows you the difference of creating a lookup in Javascript for both CRM 4 and CRM 2011

I would defintely recommend having the Javascript cheat sheet close to hand when you start developing

Custom Workflow Changes:

Filed under: CRM 2011, CRM 4