In July 2010, Microsoft transitioned from providing mainstream support for Windows Server 2003 to releasing critical patches only. July 14, 2015 marks another transition, this time the end of Microsoft support for Windows Server 2003/R2. The end of support and the end of life of Windows Server 2003 means that your business needs to ensure that it has a plan to migrate the applications and workloads currently relying on Windows Server 2003 onto Windows Server 2012 R2.