Nokia has announced that its Symbian platform is no longer open source. The news comes less than a year after the now-defunct Symbian Foundation released the first completely open version of the OS, with Nokia saying that its “open and direct” model referred to its business plan rather than the Symbian source code.

With complete control of the platform having reverted to Nokia late last month, the manufacturer announced that “we are not maintaining Symbian as an open source development project.”

Under the new set-up, developers will be required to register for a licence to access the source code for the OS. According to Nokia, this will “enable us to continue working with the remaining Japanese OEMs and the relatively small community of platform development collaborators we are already working with.” In addition, Nokia will monitor registrations and will only approve those which collaborate with Nokia.  Last week, Nokia announced the online re-launch of the Symbian code in a post entitled “We are Open!” When software legalese blog Groklaw inspected the licence and declared it non-open, Nokia was inundated with queries, prompting the latest announcement clarifying the position.

Although many observers believe that this looks like another step in the slow winding up of what was once the world’s leading mobile platform, Nokia has said that it plans to ship at least 150 million Symbian smartphones in the coming year. The company will also continue to offer software updates for the platform.