Mainstream support for Microsoft Dynamics 4 expires in April 2013. After this date Microsoft will no longer provide free updates and non-security fixes for Microsoft CRM 4.
Extended support will be available until April 2018. Extended support provides similar features to Mainstream Support but requires paid support cases to be opened with Microsoft. Here you can find more information on extended support.
Recently; Microsoft published Rollup 21 for Microsoft Dynamics CRM 4 – this is widely believed to be one of the last updates for Microsoft Dynamics CRM 4.
Table of Microsoft Dynamics CRM Support End Dates
|Products Released||Lifecycle Start Date||Mainstream Support End Date||Extended Support End Date|
|Dynamics CRM 3||01/12/2005||12/04/2011||12/04/2016|
|Dynamics CRM 4||29/02/2008||09/04/2013||10/04/2018|
|Dynamics CRM 2011||18/05/2011||12/07/2016||13/07/2021|