Bip39 root key https://giphy.com/channel/ebliciwsah Although it makes use of BIP32 system you'll be able to continue to import BIP39 seeds into Electrum wallet. Also aside from BIp32 there is BIP44 version which some wallet use to the generation of seeds. BIP39 solves this by making use of human-readable seed phrases https://linktr.ee/bip39