Ontology's mainnet stopped producing blocks on Aug. 31 after its core development team flagged a potential security concern during a routine daily check. The team suspended block production and launched a comprehensive security review alongside network validators.
The chain's explorer showed block 20,770,893 as the last confirmed block at the time of the halt. On-chain transactions are not being processed while the suspension holds, and Ontology advised users to avoid time-sensitive transfers until an official resumption announcement.
Ontology's statement drew a clear line between a precautionary halt and a confirmed incident. The team said it found no confirmed security event, no indication of theft, and no compromised assets. ONT and ONG tokens, along with other on-chain assets, are unaffected based on its current assessment. Users do not need to move their holdings in response to the announcement.
The pause carries no set end time. Ontology said block production will not restart until the network has been assessed and deemed safe, with a separate announcement preceding any resumption.
Ontology runs a dual-token model. ONT handles governance and staking; ONG, short for Ontology Gas, is the utility token used to pay transaction fees. The chain has operated its mainnet since June 2018 and positions itself as a trust and identity layer for Web3 and AI applications, with ONT ID as its core identity framework.
The halt came roughly 10 days after Ontology completed its v3.1.2 mainnet upgrade, which added several Ethereum opcodes to the chain's EVM. Ontology did not link the upgrade to the current security concern, and no connection has been established between the two events.
Bithumb and Upbit, two of South Korea's largest crypto exchanges, suspended deposits and withdrawals for ONT and ONG following the network pause. Exchange suspensions of this kind are standard practice when a chain halts block production, since unconfirmed transactions create reconciliation risk for custodians.
Ontology's halt came the same day Cronos stopped its entire network following a roughly $75 million exploit of the Tectonic lending protocol. The two events differ in cause—Ontology's is a precautionary review, Cronos's was a direct response to a confirmed exploit—but the timing puts two separate chain halts in the same 24-hour window.
