Older iPhones are not secure for storing a recovery phrase.

Older iPhone models, from the 4S through the X, are no longer considered secure for storing crypto seed phrases, according to Cryptoast, because they carry critical vulnerabilities that can no longer be patched via iOS updates. The warning matters for self-custody users who keep recovery phrases on retired devices, since an exposed seed phrase means full loss of wallet funds with no recourse. The article does not name specific exploits or affected iOS versions, and no funds lost or incidents were reported. Users should watch for follow-up guidance from wallet providers and security researchers on safe storage alternatives, such as hardware wallets or offline backups.