According to Odaily Planet Daily, the Stacks Foundation said that the core developers said that the Nakamoto testnet hard fork planned this week was successfully activated. Please note that the testnet may be reset over the weekend to eliminate some problems found by core developers.
During the testnet upgrade, core developers discovered some bugs related to the way nodes communicate about the retention period extension. The testnet is mostly operational, and core developers are working to iron out the last few issues and hope to make slight adjustments to the mainnet hard fork block, with plans to release an update on the hard fork details before October 4th.