Solana internals Part 2: how is a Solana program deployed and upgraded

What happens inside Solana when you deploy a smart contract to the Solana Mainnet? Can a Solana program be modified or closed? How to upgrade a Solana program? Who is authorized to change a Solana program?

This article focuses on the upgradability of Solana programs and highlights some intricacies.

Here is a list of take-away notes:

• Solana programs can be modified and upgraded (by default)
• The BPFLoaderUpgradeab1e loader is the owner…