The Lumia Denim update has started rolling out to the T-Mobile Nokia Lumia 925. It bumps the software version to 3051.50009.1451.0018, and brings along new features and stability improvements.
The update, which is roughly 530MB in size, should be available for download OTA now. To check, go to Settings -> Phone Update and then tap on Check for updates.
If you receive the error 'Update needs more space' while performing the update, head to this T-Mobile support page.
Source | Via