Creating upgradeable contracts from Solidity, is it mandatory to use App.sol?

[abcoathup]

Hi @rdemeraT,

Welcome to the community

You would only use App.sol if you were creating Ethereum Packages but the plan is to remove this contract. (See OpenZeppelin/openzeppelin-sdk#1488)

I haven’t ever used App.sol myself whilst creating upgradeable contracts.

To learn more about upgrades see the Learn guide: Upgrading Smart Contracts

• Buidler user: Create an upgradeable contract using OpenZeppelin Buidler Upgrades
• Truffle user: Create an upgradeable contract using OpenZeppelin Truffle Upgrades