And what does 'vigilant' mean exactly for mere mortals?!?

Binance founder and former CEO Changpeng Zhao, CZ, issued a warning regarding the dangers associated with wallet software upgrades that alter derivation paths. This comes in response to a situation highlighted by user Davincij15, where a wallet software upgrade led to an unscanned old address, causing a Bitcoin balance to become 'invisible.' CZ emphasized the significant risks involved in such software upgrades, noting that those which change derivation paths are "really bad and scary". He advised users of self-custody wallets to remain vigilant against these potential issues.