Upgrades

This is Part 4 of the Solana Program Lifecycle series. In Part 3 we saw that a program is two accounts: a 36-byte Program Account that points to a ProgramData Account holding the actual bytecode. Now we look at how those two accounts get created and replaced. The short version: there is a third account involved. A temporary one. It exists only during the deploy or upgrade, and if anything goes wrong, it can sit on chain holding your SOL until you reclaim it. ...

This is Part 3 of the Solana Program Lifecycle series. In Part 1 we covered the account model. In Part 2 we covered compute units. Now let’s look at something most developers never think about until something breaks: how programs actually live onchain. Because here’s the thing: a Solana program isn’t one account. It’s two. And the relationship between them is what makes upgrades possible without breaking everything that depends on the program. ...