What is Ironwood?

Zcash changes over time. Every so often the network goes through a network upgrade — an agreed point where new rules take effect, everyone's software switches over together, and the chain carries on as one.

Ironwood is one of those upgrades, known formally as NU6.3. It activated at block 3,428,143.

What it added

Ironwood introduced a new shielded pool — a new compartment of the Zcash network where private funds can live.

Zcash has had several of these over the years. Each one improved on the last: smaller transactions, faster proofs, better privacy. Sapling replaced Sprout; Orchard replaced Sapling; Ironwood is the newest.

You do not have to understand the cryptography that separates them. What matters is a practical consequence.

Why this affects you

Your wallet's funds live in a particular pool, and the server you sync from has to understand that pool.

Zecboat holds funds in the Ironwood pool. Most servers understand it. Some — usually older ones that have not been updated — do not.

And here is the part worth remembering, because it is alarming the first time it happens:

A server that does not support Ironwood will show you a balance of zero — for funds that are really there.

Nothing has been lost. The funds are on the chain exactly where they were. The server simply cannot see into that compartment, so it reports nothing, and your wallet faithfully displays the nothing it was told.

What to do about it

If your balance reads zero and you are confident it should not:

1. Do not panic, and do not start restoring from backups. A restore will not help, because nothing is wrong with your wallet.
2. Check which node you are connected to. Zecboat shows the node actually in use in Settings.
3. Switch to a server that supports Ironwood and let it sync again. Your balance returns because it never went anywhere.
4. If the balance card says "needs a rescan", go to Settings → Wallet Management → Rescan from Height.

A well-behaved wallet should tell you when its server cannot serve the pool your funds are in, rather than quietly showing zero. Not all of them do yet.

The short version

Ironwood is the current shielded pool on Zcash. Your funds live in it. The server you sync from must understand it — and if it does not, you will see zero rather than an error.

Zero is not the same as lost. Almost every time, it means the wrong server.