In this blog post we will go through the history of bitcoin wallets, and how they have progressed. Table of Contents Early Days Progression of BIPs BIP39 - Wallet Seed Creation Standardization Descriptor Wallet Backup Standardization XPUBs vs ZPUBs vs YPUBs Watch-only Wallet Early Days Before the introduction of BIPs (Bitcoin Improvement Proposals) and the development of HD wallets, bitcoin users primarily relied on simple software wallets that stored a single private key and associated bitcoin address.