In 2014 Microsoft released some hotfixes for cover issues with .NET Framework 4.5 and Exchange Server 2013 on Windows Server 2008R2 and Windows Server 2012. The .NET Framework 4.5.1 for Windows Server 2012R2 already contains the mentioned fixes. So no additional fixes are required on Windows Server 2012R2
After installing .Net Framework 4.5.2 on Windows Server 2008R2 or Windows Server 2012 it is not required to configure the DisableRetStructPinning.
The hotfixes and the included tuning of the store work process do ot have any impact on the sizing guide for Exchange Server 2013.
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