Privacy coin Firo will activate an emergency hard fork at block 1,371,000 on September 4, 2024. Nodes, miners, exchanges, and wallets are required to upgrade to v0.14.18.0 to address the Spark token inflation vulnerability disclosed in August. The vulnerability allowed the forging and inflation of FIRO tokens, with researchers minting approximately 200 FIRO during controlled testing. A temporary defense was implemented in v0.14.17.2 by limiting single inputs, and this update fully resolves the issue using versioned Chaum V2 proofs and a new transaction format.