Overview
To run some server platforms and services on Windows Shared Hosting Module at POA 5.4, there was a dependency on Microsoft Hosted Messaging and Collaboration (HMC or MPS) 4.5. HMC was built to run on top of Windows Server 2003 and SQL Server 2000 or 2005. Neither HMC nor SQL Server 2000/2005 are supported by Microsoft anymore.
To solve this issue, starting on POA 5.5, this dependency was removed and all the latest Windows-based server platforms and services are running on a new provisioning platform, called Parallels Windows Provisioning Engine (WPE). WPE provides to users the same functionalities HMC provided, but instead it runs on top of Windows Server 2008 and SQL Server 2008.
When upgrading to POA 5.5, in case there are old services running on HMC, they will still work normally. However, it will not be possible to upgrade any of these services further than 5.5 on top of HMC. All of them will have to be deployed on top of WPE instead. New PA installations will only be able to deploy WPE.
Services supported by WPE
The table below shows which services are supported by WPE in POA 5.4 and POA 5.5. Note that Legacy services are not supported by WPE on any POA version.
| Service | POA 5.4 | POA 5.5 | Not Supported |
| IIS 7.5 | - | Yes | - |
| IIS 6/7 | - | - | Yes |
| SharePoint 2/3 | - | - | Yes |
| SharePoint 2010 | Yes | Yes | - |
| MS SQL 2000/2005 | - | - | Yes |
| MS SQL 2008 | - | Yes | - |
| MS DNS | Yes | Yes | - |
| Hosted Exchange 2003/2007 | - | - | Yes |
| Hosted Exchange 2010 SP2 | Yes | Yes | - |
| Hosted Exchange 2013 | - | Yes | - |
| Good Mobile Messaging | - | - | Yes |
| BlackBerry Enterprise Server 5 | Yes | Yes | - |
| Hosted Dynamics CRM 4 | - | - | Yes |
| Hosted OCS 2007 R2 | - | - | Yes |
| Windows Streaming Media | - | - | Yes |
| ColdFusion 6/7/8 | - | - | Yes |
| Branding and UI Servers | Yes | Yes | - |
| WinFileManager | - | Yes | - |
| AWStats Web Statistics | - | Yes | - |
| SQL Server Web Data Administrator | - | Yes | - |
| myLittleAdmin for MS SQL Server | - | Yes | - |
| Domain Parking on MS IIS | - | Yes | - |
| SSL Proxy on IIS | - | Yes | - |