Warning: Mainnet USDT cannot be distributed from Immutable V2 Splits
If you are reading this, your funds are safe. Everyone with existing Mainnet USDT balances in an immutable V2 Split has been contacted and reimbursed.
TLDR: USDT on Mainnet is not an ERC20 token, which means it's not compatible with Splits V2. We've shipped Splits V2.1 to address this.
If you are using an immutable V2 Split on Mainnet and it might receive USDT in the future, please create a new Split via our UI or the latest SDK. If you’re not sure if your Split is V2 and immutable, open your Split in our app. If your Split is affected, you will see a message at the top of the page.
What happened?
In May, we released a new iteration of Splits (V2) with important multichain UX improvements. In December, we received a bug report that a user was unable to distribute USDT from their Mainnet Split. Upon investigation, we found that USDT on Mainnet is not ERC20 compliant and that this edge case wasn’t handled properly in V2 Splits. Fortunately, the Split had an owner: the owner is able to manually grant USDT approval, which allows the Split to continue functioning as-is.
After helping this user, we analyzed the chain to find other impacted users. When we didn’t find any other impacted users, we figured that if existing Splits hadn’t received USDT on Mainnet by now, they were unlikely to do so in the future and we could just quietly ship an update. This was a mistake.
Since shipping an update iteration in January (V2.1), we’ve had two further instances of V2 Splits receiving USDT. Unfortunately, neither of these Splits had owners and so the funds were stuck. Both of these losses were avoidable if we had communicated better publicly, and so we compensated them appropriately and are now fixing our mistake in the hopes of avoiding future losses.
What has Splits done?
We shipped a new iteration (V2.1) in January to the app and SDK. For existing V2 Splits, we’ve added a prominent warning in the app and are now broadcasting this message as widely as possible.
What should I do?
First, double check your Split in question is impacted by visiting our UI (see above).
If your Split is impacted and you might receive USDT in the future, stop using it and create a new one. If your Split is mutable and you would like to continue using it, please see this help center article on how to fix it.
If you’re a developer relying on our SDK (V4) to create immutable V2 Splits on Mainnet that might receive USDT, upgrade to the latest version. If you’re using an older version of the SDK that creates V1 Splits, you are unaffected.
What next?
Shipping smart contracts is hard. Even when the system works exactly as expected (e.g. handles ERC20s), things still go wrong (e.g. one of the largest stablecoins is not actually ERC20-compliant on every network). We take security very seriously, but even after multiple reviews and audits, things will occasionally slip through the cracks. What is not excusable, however, is not communicating quickly and directly with our users. This is an important learning lesson for us, and a mistake we won’t make again. Thanks for your support.