Addictive sandbox adventure Minecraft from indie developer Notch will hit beta on December 20th, the developer’s blog announced today. An extreme alpha version is available to the public as a web game and a more developed downloadable version is available to those who pay a fee of €9.95. These paid players are also promised every further version of the game as a free upgrade.

From December 20th onward, access to the latest version of Minecraft will cost €14.95 and will not include free upgrades to all further updates. All existing paid players will receive free updates for the rest of the game’s life cycle, but beta players will be forced to pay for the final version of the game upon its release.

On the changes introduced in the beta, Notch said “With Beta comes a larger focus on polish and content, and we’ll start early on with adding proper modding support with a stable API, and we’d love all input we can get on this from the modders out there. We’ll also add some kind of non-intrusive narrative to the game to help drive the game experience early on, and to provide some kind of late game goal. There will be a bigger focus on testing and stability as well, with more time between updates.”