Clocks, old phones and other edge cases

What happens when the offline device's clock is wrong, when saved data will not open, when a network upgrades, and when the online computer lies.

This page covers the unusual cases: a wrong clock, saved data that will not open, a lost device, a network upgrade and a hacked online computer.

#A wrong clock on the offline device

Offline phones often have the wrong date. A phone that restarts without a network can come back years in the past. Signing never depends on the clock, so a wrong one cannot stop a payment:

• Bitcoin: the signer accepts a lock time only as a block height, and refuses one given as a date
• Ethereum, Solana and Monero: signing does not read the clock
• Zcash: transactions expire at a block height, and the signer judges that against the higher of 2 numbers, the last height it was shown and the height today's date suggests

The clock does matter in 3 places.

#Where new Monero and Zcash wallets start scanning

A Monero or Zcash wallet scans the blockchain for its payments, starting from the date it was made. Other wallets call this its birthday. A wallet made on the offline device takes that date from the device's clock.

A clock that is behind only makes the first scan longer. Since October 15, 2026, the start is never earlier than the day before your copy of AirWallet was built, so a clock that jumped back years does not mean years of blocks. A 16-word Polyseed records its month the same way, with the same rule.

A clock that is ahead by more than a day can make the scan start too late, so earlier payments do not show. Your money is not lost, only hidden until a scan covers it. The everyday device catches a start that lies past the chain's current height: it scans from a week before the current height instead, and says "since" with that date. For a start that is late but not past the current height, scan further back yourself: ⋯ → Monero: scan from a date… or Zcash: scan from a date….

#App lock waits

After 5 wrong PIN or password tries, the app lock makes you wait: 30 seconds, then 1 minute, then 2, doubling up to about 2 hours. Quitting the app does not reset the count. Before October 15, 2026, a clock set back by a restart could stretch that wait into years. Now, any wait longer than the longest possible one starts again from now.

#The device warns you

Every balances code from your everyday wallet carries that computer's time. When the offline device scans one, it compares clocks. Once per start, it tells you if its clock is more than 10 minutes behind or more than 3 days ahead, for example "This device's clock is 3 days behind your online computer's: set its date and time". Setting the date and time works in airplane mode.

#Old phones and factory resets

An offline phone cannot update its web engine, and a factory reset puts back the one it shipped with. Android 10 and later run everything as they come. Android 7 to 9 need one web-engine update while still online. If one coin cannot run, AirWallet names it once and the other coins keep working. Platforms and compatibility has the versions and the update steps.

#Saved data that will not open

Sometimes an app cannot read its own saved data. On Android, a glitch in the phone's key storage can cause it. So can a damaged file, or data saved by a newer AirWallet.

Some wallets have started empty at that point, and their first save destroyed the real data. AirWallet never saves over data it could not open. It shows Your saved wallets didn't open, with 2 choices:

• Try again
• Keep them aside and start fresh, which leaves the old data on the device, untouched, while you bring your wallets back from their words or a backup file

If a newer AirWallet saved the data, the app asks you to update this copy and says nothing was changed.

#A lost or stolen device

Your coins are on the blockchains, and your words bring them back. The wallet's data on the device is encrypted, and with the app lock on, nobody can open the app without your PIN or password.

1. On any copy of AirWallet, select + → Import and enter your words, or import an encrypted backup.
2. Move the money to a new wallet, in case someone gets into the old device.

Without the words or a backup, the coins are gone, and nobody can recover them. Turn on the app lock and keep an encrypted backup before anything goes wrong. See Backups and recovery and App lock, duress PINs and disguises.

#Network upgrades

Sometimes a coin's network changes its rules, and transactions signed under the old rules stop being valid.

Zcash's NU7 upgrade is due around November 5, 2026, with its exact block height set in node releases due October 20. Copies built since October 15, 2026 are ready: they learn NU7's height from the Zcash server, and the offline signer accepts NU7 transactions. If an update comes out before then, install it on both devices.

Monero's FCMP++ upgrade has no date yet. Before each send, the everyday device asks its Monero node which upgrade the network is on.

If a network moves to rules your copy does not know, AirWallet refuses to send and asks you to update both devices. The offline device is the slow one to update, so update it as soon as a release is out. See Updates, downloads and outside code.

#A hacked online computer showing fake balances

The offline device cannot look anything up. Its balances come from your everyday wallet's codes, and it labels them "as your online wallet reported". A hacked online computer could report anything, so these balances are for display only:

• nothing the signer signs depends on them
• a report that a send "failed" never makes the signer sign the same payment again, and Show again shows the same signed transaction, which can land only once
• the review warns you if a payment looks like one you already signed, or is more than the wallet had

If balances look wrong, check your addresses on a block explorer from another device.

#Two copies handing out addresses

Two copies of AirWallet can each hand out Bitcoin receive addresses the other has not seen. To catch payments to those, the everyday wallet looks 20 addresses ahead once a day and after an import.

With Monero, 2 devices may hand out the same subaddress. That costs privacy, not coins.