The WPBench data reveals a new Windows Phone 8.1 update 1 Build 8.10.14219.0. This is an incremental build over the last released Developers preview build 8.10.14203 and which brought some useful features like scheduling Windows Phone updates, using SD card for updates and enabling Battery saver Live Tile.
In fact, if you check all the last Builds of Windows Phone 8.1 update 1 aka GDR1 have been incremental only. 8.10.14192.280 which tested critical update capability or 8.10.14176 before that which brought update error fixes and spread the update to HTC devices. The update version 8.10.14157 before that was incremental too.
Anyways, while new versions popping up not always confirm update roll out, but considering the above history of incremental WP8.1 GDR1 updates, it may be a good candidate of rolling out to dev preview devices.