To future-proof your Move modules on Sui without breaking compatibility, you need to plan for upgrades carefully since published modules are immutable, but Sui’s package upgrade system lets you roll out new versions that maintain compatibility while adding or tweaking functionality. One of the best strategies is using a “master object” pattern, where a central object (like a Version or Config object) stores the current logic version and pointers to active modules, allowing you to redirect calls to updated logic without changing existing interfaces. You can define this object in your initial module with a version field and an upgrade function, like public fun update_version(config: &mut Config, new_package: address), ensuring it’s only callable by authorized parties (e.g., using an UpgradeCap). This keeps your app’s public API stable, so users or other contracts don’t break when you publish a new package with updated logic. Another approach is to design modules with modular, additive changes—keep public function signatures and data structures unchanged in new versions, only adding new functions or fields, and use compatibility checks (sui upgrade --verify-compatibility) to catch issues before deployment. For shared objects, include version tags and migration logic to handle data updates smoothly, like transferring balances to new structures. In practice, the master object pattern shines for complex apps like DeFi protocols, as seen in projects like Cetus, where it simplifies logic swaps without disrupting users. Be cautious of security risks—restrict upgrade permissions tightly, ideally with a multisig or DAO, to prevent malicious changes, and test upgrades on Sui’s testnet to simulate real-world impacts. Avoid over-relying on shared objects, as they can complicate migrations due to consensus requirements.