Developers can now access Windows Phone 8.1 code, Microsoft announced on Monday, as part of the Windows Phone Preview for Developers programme. Other users will have to wait for their network operator to push out an update or buy a new handset.

The software giant unveiled Windows Phone 8.1 at the start of April, adding more customisation options and new keyboard input support in the form of Shape Writing.

Most Windows Phone users will have to buy a new handset with the first models shipping with Windows Phone 8.1 due in May or wait until their network operator gets around to pushing out updates for their current handset sometime in the coming months.

But developers who have signed up to Microsoft's Windows Phone Preview for Developers programme will be able to get their hands on the code today. Introduced last October, this scheme gives registered developers access to pre-release Windows Phone operating system updates for their development phone, delivered directly from Microsoft itself.

Writing on the Building Apps for Windows blog, Cliff Simpkins, senior product manager for Microsoft's Windows Phone Developer Experience group, said that the programme enables developers to start building apps before the platform ships to consumers.

"We make these updates available to you to enable on-device testing, and to enable you to build and test platform capabilities not present in the emulator," he said.

Along with the tooling delivered in Visual Studio 2013 Update 2 RC, developers can now get everything they need to start building and testing Windows Phone apps and universal Windows apps, the firm said.

In order to participate in the Windows Phone Preview programme developers must be registered on the Windows Phone Dev Center, be a registered developer with Windows App Studio, or have access to a Windows Phone device that is developer unlocked, which can be accomplished using the developer phone registration tool.