Even though Mk4 and up are slightly better, they still have drastically reduced private key security (2^32 instead of 2^128 as they should) and so keys are still possible to brute-force. It will take more time, but you should assume any seed generated on a device + firmware below is vulnerable and will be compromised at some point. Don't panic, though, just take a minute to plan through what a safe and reasonable migration plan is for your stack and execute it ASAP. The two primary paths you can take: 1. If you already have an additional, non-Coldcard hardware wallet lying around - update that device, generate a new seed, and move funds immediately. I'd recommend something open-source and up to date like a @FoundationHQ Core or Prime, or a @Trezor recent model. 2. If you don't have another hardware wallet already, consider migrating funds to Cupcake (cupcakewallet.com), which lets you turn an old Android or iPhone into an offline, air-gapped signer. You can use it to generate a new seed phrase, move funds onto it, and if you want to later move to a hardware wallet you can easily do so (either by importing the Cupcake-created seed or creating a new one on the new device and sending funds). THINGS TO BE WARY OF: 1. Don't rush to send your funds and make a mistake in address or fall for phishing. Expect spear-phishing out of this that targets people panicking. 2. Understand that sweeping your entire stack in one transaction will link those UTXOs together permanently, which is very, very bad for privacy. Consider taking the time to move individual UTXOs, one at a time, to new addresses. @cakewallet (Q-only) and @SparrowWallet are two apps with Coldcard compatibility that make this easy to do with coin control tooling.