Why wallets need a nudge today
Shielded Zcash wallets find payments by scanning the chain. When an app has been closed for a while, it falls behind and cannot tell you the moment you are paid. Phones also limit background work: iOS offers BGAppRefreshTask and Android offers WorkManager, but the operating system decides when those run. Lantern Zero adds a server-scheduled silent push every 30 minutes as another wake source, plus optional scanning for alerts within seconds.
Your wallet's own schedule
Wallets should keep their own background sync. That schedule comes close to a keyless ping, especially on Android. The Lantern Zero ping is one more wake on top of it, and it may matter more on iOS, where background refresh is discretionary. The project has not yet measured silent pushes against BGAppRefreshTask and FCM against WorkManager on real devices; if the pings are no more reliable than the OS, the public README will say so and the channel may serve mainly as cover for scanning users.
What scanning covers until Tachyon
While Tachyon is still on the roadmap, wallets still trial-decrypt blocks locally or lend a viewing key for faster alerts. Scanning mode provides instant shielded payment notifications, a hint list, and live updates while the wallet is open. Those features depend on the server watching the chain on your behalf for the life of a short lease.
After Tachyon ships
Tachyon is meant to change how wallets discover shielded payments, so the scanning service is expected to retire. The wake-up channel is designed to remain for scheduled sync nudges. Whether that stays worth running depends on how quickly a wallet can catch up when opened and on which Tachyon services third parties are expected to operate, such as PIR databases, oblivious sync, or an introduction service. That division of labor is not settled here.
Default mode and the crowd
Even when a ping adds little freshness, default mode still sends the same contentless wake to every device and the same padded requests, so an observer cannot tell who has lent a viewing key. That privacy reason goes away when scanning retires, unless Tachyon still leaves some outsourced request that needs the same cover.
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