A user mail carried two reports, and both turned out to be real.
His Brother MFC-J497DW woke its display every five minutes, exactly when the DeviceShelf server ran its scan. The cause is the SNMP question the scan asks every device. Most hardware answers it silently; some printers treat it as a reason to light up. There was no way to spare a device from that.
Now there is. Every device has a switch in its drawer: exclude from active scans. With it set, DeviceShelf sends that device nothing. No port scan, no SNMP question, no direct name queries. Passive discovery and the presence ping stay, so the device remains on the list and keeps being monitored. It just stops being interrogated.
The first version of that switch had a hole, and I would not have found it alone. An independent review of the change noticed that name resolution starts while the scan is still sweeping, at a moment when a row has an address but no MAC yet. A switch keyed on the MAC could not match there, and the printer would have been queried through exactly that path. The exclusion now also matches on the device's last known address. There is a test that watches the wire and fails if an excluded device receives a question.
The second report: his Unraid server, running 24/7, kept going offline in ntfy and coming back. The mechanism was embarrassingly simple. Between full scans, the server pings known devices every 30 seconds, and one unanswered ping (750 milliseconds of patience, once) counted as an outage under the default settings. A machine that briefly deprioritises ICMP, or a Wi-Fi hop that drops one packet, produced the exact pattern from his mail. An absence now needs three consecutive misses before it counts. A lost single ping no longer stains the uptime ledger. And every offline event states how it was established, "missed full scan" or "no reply to 3 probes", so if anything still flaps, the event log says where to look.
While proving all this with tests, a third defect surfaced: the per-device "mute notifications" switch, which the dashboard has offered all along, was stored by the server and then ignored at the moment of delivery. Muted devices notified anyway. That is fixed, with the semantics you would want: the timeline entry, the alarm state and the outage record stay. What you muted is the pushing, not the monitoring.
Also in 1.9.4: icon search now works in every language across the full set, and the picker can browse by group instead of search-only. Custom icons and custom types reach the server dashboard and the phone, and your own types are listed before the built-in ones. A machine with two network cards is one row instead of two, and a type you assigned survives that merging. The server writes its store with half the CPU it used before. A running packet capture stops by itself when nobody is watching it.