As many of you know, a soundness issue was discovered with version 1 of the Triton VM proof system. For this reason, on January 21 2026, the blockchain was paused, and on February 4 2026, the blockchain was rolled back to block 23400 and operations resumed with Triton VM version 2 where the soundness issue has been fixed. For ten weeks, the blockchain has now been relying on Triton VM version 2.
A problem with privacy-preserving blockchains such as Neptune, though, is that only the sender and receiver can see the amounts being transacted. So there is a remote possibility that the soundness problem in version 1 was exploited, although we have every reason to believe it was not.
This is admittedly a drawback of privacy preserving blockchains: On Bitcoin, Ethereum, and other see-through blockchains, any such extra inflation of the money supply could quickly be identified and rolled back, because all amounts are publicly visible. On a privacy blockchain, you have no such niceness: you cannot see if past soundness problems have been exploited to increase the money supply. So other tools have to be used.
As we stated in the Neptune Cash v0.6.0: Resuming Operations blog post, we want to eliminate the remote possibility that the soundness error in the old version of Triton VM has been exploited to inflate the money supply beyond the intended amount. Therefore, we have prepared a so-called lustration barrier where users with old UTXOs must disclose the input amounts when they are being spent. Disclosing all input amounts and decrementing a global counter means that we can count, and cap, the value of all old UTXOs being spent, thus giving all current and future holders a guarantee that their share of Neptune coins have not been inflated away by an attacker.
Technically this is archived by requiring that all inputs that were generated prior to the activation of the upcoming hardfork beta must reveal the input values to their transactions. The size of the on-chain announcement in this process has been shown to be quite small, meaning that it will not impose significant additional costs transaction fee costs.
We do, however, still recommend that users with many UTXOs consolidate their UTXOs into ones of higher value. If you’re running an exchange, a mining pool, or you’re doing transaction upgrading and collecting fees for this, you should consolidate your UTXO into high value ones prior to the activation of hardfork beta, as this means you only have to “carry over” your UTXOs few times, thus reducing the negative impact the lustration barrier has on your privacy, and reducing the transaction fees you have to pay for future transactions.
The lustration barrier is expected to be activated at either block height 38,000 (~ May 13 2026) or at block height 40,000 (~May 27 2026).