Apprenda has just launched rev 4.0 of its flagship private Platform-as-a-Service (PaaS), claiming the new eponymous, uniquely single-language widgetry will be the model for how to modernize existing mission-critical enterprise applications and build new cloud-architected apps and services.

Well, so long as they're Windows apps and Windows-based cloud environments. Ah, but then let's remember that 40% of the apps running the enterprise, many of them custom-made, have Windows written all over them.

See, the once strictly on-premise Apprenda PaaS has been extended to Microsoft Azure and by connecting Windows Server 2012 environments with cloud-based Azure resources creates a hybrid cloud PaaS for the Global 2000 it caters to. The company describes it as extending the data center to Azure.

It claims the private PaaS is the now generally accepted end game for the enterprise, primarily because of the regulations and requirements that restrict an all-public cloud approach. It also figures that other people do hybrid poorly.

Its 4.0 platform achieves a hybrid PaaS/cloud in a single click with instant scaling options to meet application consumption needs. That means it essentially creates one big clearly seen cloud and since the apps on-premise and the apps in Azure all behave the same way companies can make business decisions that aren't limited by the technology.

Apprenda CEO Sinclair Schuller says enterprises, despite compliance and governance hesitancy, want hybrid cloud architectures to test at least some of their workloads on the public cloud or to extend the life of older apps by making them multi-tenant.

With 4.0 IT can apply resource policies to infrastructure and applications before moving them in seconds from the private to the public cloud or set policies for doing so automatically based on business needs and parameters.

RedMonk's founding analyst James Governor is quoted as saying, "Hybrid cloud is helping traditional enterprises become more comfortable with .NET-based application development. Organizations want common tooling for deployment, monitoring, security and management across public and private cloud; Apprenda is targeting this deployment flexibility directly with its 4.0 release."

As a so-called best-of-breed platform for Windows Server and .NET, Apprenda 4.0 adds support for all Windows and Visual Studio integration and extends support for all of Microsoft's latest releases including .NET 4.5, SQL Server 2012 and Windows Server 2012. The company says existing apps usually require only minimal code tweaks to make the great leap to the cloud.

Apprenda had integrated 4.0 with third-party and customized authorization and authentication systems to improve agility in application deployment and deployment policies in implementing governance, risk management and compliance (GRC). With new System Center 2012 integration, it can run across multiple data centers (private/public/hosted) and yet be managed centrally.

By decoupling applications from the infrastructure and developers from IT, Apprenda figures it lets organizations achieve significant cost savings and massive productivity improvements.

"Windows Azure is a global scalable cloud platform that gives developers flexibility to target public, private and hybrid cloud environments," Azure marketing general manager Bill Hilf says. "Apprenda helps enterprises utilize Windows Azure's strengths so that applications can take advantage of public and private PaaS scenarios."

Apprenda is priced by the gigabyte of memory. The company, which figures the 2013 PaaS market is going to come down to price, offers freeware but it's not pursuing the freemium model. The full-function Apprenda Express freeware, limited to 12GB of memory, is generally used for proof-of-concept. Although it's got about 7,000 companies experimenting with Express, Apprenda is focused on accounts with at least $4 billion in annual revenues. Figure a paid Apprenda installation runs from the high five digits to the low seven digits.

Schuller expects VMware to pursue a similar strategy using its own open source Cloud Foundry PaaS and CloudFoundry.com, the public instance of Cloud Foundry running on vSphere infrastructure, now in beta. He doesn't think VMware (or what may be a new EMC subsidiary according to GigaOm) can manage a cloud to rival Amazon or Azure before late 2013 or 2014.

Apprenda launched in 2007 and has raised around $16 million from High Peaks Venture Partners, Ignition Partners and New Enterprise Associates.