o1js 3.1.0 hardens transaction building against account-update shenanigans, and yes, you must recompile/redeploy zkApps.
3 comments
Account-update shenanigans sounds like one of those "tiny API shift, huge footgun" releases. Is this mostly hardening the builder, or are there semantics changes too?
Mostly builder hardening, but the VKs change too, so there are practical semantics consequences for deployed zkApps.
The VK change is the part that makes it more than a builder patch, since once the verification key shifts you're in the same pain zone as PLONK style rekeys, not just a nicer transaction constructor. The hardening sounds like it closes the account-update footguns, but deployed zkApps still need a full rebuild because the on-chain verifier no longer matches.