Nokia has announced via a new blog post that the next iteration of their in-house smartphone operating system will be called Nokia Belle. The OS was previously referred to as Symbian Belle and it is unclear why Nokia made the name change.

Earlier this year, Nokia announced a partnership with Microsoft that would make Windows Phone the primary operating system for the company. Symbian became a franchise platform used on feature phones but will remain relevant at least until Windows Phone devices become widely available.

As CNET points out, it's unclear if the renamed OS is a permanent change or just a simple change for a specific software version. Either way, Nokia Belle will include all of the features previously announced for Symbian Belle. Key features include six home screens (previously three) and redesigned widgets for email, music, calendar and favorite contacts. The reworked lock screen now alerts users about missed calls, inbox messages and other notifications.

Symbian Belle is already in the wild, having launched earlier this year with Nokia 603, Nokia 700 and Nokia 701 handsets. Updated versions of Nokia N8, Nokia C7 and Nokia C6-01 have started shipping to shops with Nokia Belle preinstalled. These phones will be arriving in China first before migrating to other markets.

Those currently using a Nokia N8, Nokia E7, Nokia E6, Nokia X7, Nokia C6-01, Nokia C7 and Nokia Oro will be able upgrade to Nokia Belle software starting in February 2012.