As of yesterday players can no longer download Project Spark, with the creative sandbox going completely offline on August 12. Later this summer players will no longer be able to download user-generated content, or upload their own creations.
Microsoft and Team Dakota thanked players for their commitment over on the game's official forums, explaining that with the title no longer in active development, and with individual developers being moved onto other projects, there was no way to continue supporting it.
Those who purchased the Project Spark Starter Kit or redeemed a code from a retail copy of the game after October 5, 2015, will have credit automatically added to their Xbox Live account, although no timescale for the credit was confirmed.