The March 2013 Public Update (PU) for SharePoint Server 2013 and SharePoint Foundation 2013 have been released.
The Server packages for the Feb CU are contained in the March PU and is available for download here:
This update package includes all the server component packages. Additionally, this cumulative update package updates only those components that are installed on the system. A change in the package configuration was introduced after SharePoint Server 2013 was released. You must install this public update before you install later SharePoint updates.
When you install the update watch out for SharePoint farms where search components and high availability search topologies are enabled. For servers that include search components, you have to follow specific steps to ensure that you install the PU correctly. For a high availability search topology, you use Windows PowerShell cmdlets to patch a Search service application. The steps to follow are mentioned in the following Microsoft website:
How to install update packages on a SharePoint farm where search component and high availability search topologies are enabled
Update Center for SharePoint 2013 http://technet.microsoft.com/en-US/sharepoint/jj891062
One of the feature updates of the March 2013 Public Update for SharePoint 2013 is that it enables you to use multiple app domains in SharePoint 2013 environments with alternate access mapping or host-header web application configurations. Before the Public Update, you could only host ONE app domain and it had to be in the Default zone. You could not use the app domain on alternate access mappings or host-header web application configurations. The Public Update enables you to configure an app domain for each web application zone and use alternate access mapping and host-header web application configuration.
Although the Public Update automatically installs the necessary pieces, the feature is not enabled by default. To enable and use this feature, you have to use a reverse proxy to allow traffic for the app domains. The Public Update does not install or configure the reverse proxy. You must set up the reverse proxy.
See Enable apps in AAM or host-header environments for SharePoint 2013 for more information.
Due to a change in the package configuration introduced after SharePoint 2013 RTM the March Public update is a mandatory requirement in order to install subsequent SharePoint 2013 Updates.
This is build 15.0.4481.1000 of the update package.