The Bitcoin Core crew alerted on January 5 a couple of vital error within the pockets migration course of current in variations 30.0 and 30.1 of the software program.
In keeping with what was defined, “below uncommon circumstances”, when attempting to transform a legacy pockets (previous wallets saved within the Berkeley DB format) the failure could cause the deletion of all pockets information hosted on the identical node.
If there aren’t any backup copies, this would carry a direct danger of lack of funds. The event crew really useful not executing mentioned migration course of till the publication of a brand new corrected model of Bitcoin Core, on this case, akin to 30.2.
The incident happens after a 12 months of robust debate within the bitcoiner group round Bitcoin Core v30, a model that, amongst different modifications, expanded using the OP_RETURN opcode to embed arbitrary knowledge in transactions, a call that generated controversy throughout 2025.
The bug in Bitcoin Core v30 completely impacts the migration of previous wallets
Legacy pockets migration is the mechanism by which an previous pockets is transformed to the extra trendy format utilized by Bitcoin Core.
He bug It doesn’t have an effect on the final functioning of the node or the each day use of current wallets; solely impacts the act of migrating legacy wallets utilizing v30.0 or v30.1.
Bitcoin Core clarified that every one different makes use of stay intact: you possibly can proceed working a node, use current wallets, and function as regular. The repair will arrive with Bitcoin Core 30.2. Till then, the advice is to not migrate legacy wallets with 30.0/30.1.
As an extra measure, the binaries (set up executable information) v30.0 and v30.1 have been labeled “unsafe”. On the official website, the really useful obtain was as soon as once more Bitcoin Core 28.1, a earlier model thought-about steady, and which doesn’t embrace the elimination of the OP_RETURN restrict.
Reactions and criticism from the group
Bitcoiner developer Tomer Strolight referred to as the difficulty harshly:
That is fairly critical if I am studying it appropriately. If you’re attempting emigrate a legacy pockets, Bitcoin Core 30.x might delete all wallets on the system. After all, backups ought to at all times be maintained, but it surely’s so extreme that Core eliminated v30.x as a really useful model on their very own website.
Tomer Strolight, bitcoiner developer.
Strolight added that given the earlier emphasis on putting in v30 for supposed safety enhancements, there needs to be in depth and proactive communication about this bug: “Those that promoted its set up ought to elevate widespread alerts earlier than somebody loses all their pockets information.”
The episode highlights two key factors. First, the significance of backups: A pockets with no backup at all times implies danger.
Second, even in vital and audited software program errors can come up with critical penalties. The crew’s response (public alert, binary removing, and a scheduled patch) goals to comprise the impression.
Till the publication of Bitcoin Core 30.2, the steering is obvious: don’t migrate legacy wallets with v30, preserve backups and, if a steady set up is required, go for 28.1.
