Moving your funds to Ironwood

Zcash is introducing a network upgrade and new shielded pool called Ironwood. If you hold shielded ZEC in the Orchard pool (the default for Zodl), Zodl will help you move it to Ironwood. This article explains what's happening and what to expect.

For the full background, read the announcement: Ironwood: a new shielded pool for Zcash.

The short version

• Ironwood is a hardened new shielded pool. It uses the proven Orchard protocol, backed by formal verification and additional independent audits.
• If you have an Orchard balance, Zodl will prompt you to migrate it to Ironwood. Migrating is simple and upgrades you to the latest secure pool.
• Your Zodl receiving address doesn't change. Ironwood uses your existing Orchard receiver, so addresses you've shared keep working.
• You stay in control of your funds the whole time.
• Zodl will guide you through the full migration process, though read on for the background and more details.

Is anything wrong? Is my ZEC safe?

No action is needed beyond migrating when prompted, and there's no need to rush.

As explained in the announcement, a recent Orchard soundness issue was discovered through ongoing security research, responsibly disclosed, and remediated through a coordinated network upgrade in early June (labelled NU6.2). There is no evidence that the vulnerability was exploited, no evidence of impact to user funds, and no evidence of any change to the total ZEC supply. The issue did not affect the privacy of funds in any pool, and Orchard continued operating normally following the remediation.

Through Zcash's cross-pool accounting mechanism, named the turnstile, the total amount moving from Orchard into Ironwood is verified. Because the turnstile won't allow more ZEC to move out than went in, everyone receives a trustless guarantee that the circulating supply does not exceed the amount in Orchard, independent of when any individual migrates. Further, Ironwood provides users with even greater security assurances through formal verification and other audit methods deployed with Ironwood.

When is this happening?

Ironwood is targeted for activation on July 28th. Zodl will prompt you in-app when it's time.

Do I need to do anything?

When Ironwood activates, Zodl shows a migration screen if you hold an Orchard balance. We recommend completing the migration when you see it. If you dismiss it, Zodl will remind you next time you open the app.

How migration works in Zodl

Migrating is straightforward. Zodl offers two ways to do it:

With added privacy (recommended). Your balance is sent to Ironwood as several smaller transfers, spread out over time. Moving funds between pools reveals the amount of the transactions on the public Zcash blockchain (but not the originating or destination addresses), so spreading the transfers out and varying their timing make it much harder for an outside observer to link them to your wallet. Additional privacy is assured by broadcasting transactions over a different server than the one used for syncing. After confirming the plan, the transfers are then sent in the background.

Should anything fail while migrating funds in the background, Zodl will notify you and provide guidance on any next steps.

Immediately. Your balance moves in a single transfer right away. It's the fastest option, but offers less privacy because the full amount crosses over at once.

Manually. After Ironwood activates, it's possible to send funds to a shielded address (such as your own) as usual without using the Migration process, and by doing so, you're necessarily sending funds from Orchard to Ironwood. While the sender and receiver aren't exposed, these funds cross the turnstile, and thus the amount of the transaction is revealed. This has a similar effect as the immediate migration option, in that amounts and timing aren't controlled for. Therefore, we recommend the 'Migrate with Privacy' option.

What to expect with the private migration

1. A quick preparation step. Zodl first does a wallet-internal step to get your balance into smaller pieces. No ZEC leaves your wallet during this, as it's a transaction sent to yourself.
2. You review and confirm the plan. Zodl shows the full set of transfers and roughly when they'll happen. Most migrations will ask for only one confirmation, without a need to approve each transfer individually. For users with larger numbers of notes, particularly on Keystone wallets, multiple batches may need to be signed.
3. Transfers send in the background. Zodl sends each transfer when your device conditions allow. This is best-effort: if your phone was offline, asleep, or in a battery-saving mode, a transfer can be delayed, and Zodl will ask you to reopen the app to send the next one. (You will need to enable notifications as prompted within Zodl for you to receive these.) This is a normal part of the process, not an error.
4. You can watch progress. The migration screen shows how far along you are (for example, 'Transfer 2 of 5 complete') and how much is still in Orchard.

How long does it take?

It depends on your balance. Smaller balances can finish well under a day; larger balances are deliberately spread over a longer window (up to a couple of days) for stronger privacy.

Extra network privacy (Tor)

Before you confirm, Zodl offers to route your migration transfers through Tor for added network-level privacy. We strongly recommend enabling Tor, as not doing so will leak your IP address to the remote server, which can be further linked to the migration amounts. If Tor isn't available on your network or in your region, highly consider using a trusted VPN (like NYM) before continuing.

Allowing transfers to send on time

Android

On Android, Zodl may ask you to allow background updates (a battery-optimisation exemption). Granting this helps scheduled transfers send closer to their planned times. On some devices and battery modes, reminders may not always arrive – so the most reliable way to check is to reopen Zodl, which always shows your current progress and prompts anything pending.

iOS

On iOS, Zodl will require that Background App Refresh is enabled in order to send each scheduled transfer in the background. Without it, Zodl cannot operate in the background and will instead require you to approve all transfers manually when opening the app.

By default, this setting is on. However, if you have switched it off, you'll need to enable it by navigating to iOS Settings > Applications > Zodl, and toggling on 'Background app refresh'.

Frequently asked questions

Will my receiving addresses change?

No. Ironwood uses your existing Orchard receiver, so your address stays the same and previously shared addresses keep working.

Do I have to migrate right away?

We recommend migrating when Zodl prompts you, so that your funds are in the current, best-supported pool.

Do I have to use the private option?

No, you can migrate immediately if you prefer speed. The private option is recommended because it better protects your financial privacy from amounts being correlated on the blockchain.

I saw a message that transfers are 'ready to send' or that delivery was delayed. What do I do?

That's expected. Background delivery can slip on some devices. Tap Send now to send the pending transfers, or let Zodl keep trying in the background.

A transfer "couldn't be sent." Is something wrong?

Usually it just means the funds for that transfer moved elsewhere, or the transfer expired. Open Zodl and follow the prompt to create a new transfer for your remaining balance.

Can I stop and come back later?

Yes. Close the app any time and reopen it later. Your progress will be saved and Zodl picks up where it left off.

Are there fees?

Each transfer pays a small network fee, the same as a normal Zcash transaction.

Will I be able to use Swap and CrossPay, or Flexa, as normal?

Yes, regardless of whether you migrate to Ironwood. NEAR and Flexa will be compatible with this network upgrade.

Still need help?

If something doesn't look right, or your migration seems stuck after reopening the app, contact us at support@zodl.com and tell us where you are in the flow.