Yealink device registration

Update timeline

1. resolved Oct 23, 2026, 10:14 PM UTC

   Yealink devices running older firmware versions (<v84) that fetched their configurations from affected web servers (roughly 10% between 10/16-10/20, 100% on 10/21) had their configurations wiped and could not reconnect to SimpleVoIP without manual intervention. The vast majority of Yealink devices are running newer firmware versions and were not affected.

2. postmortem Oct 23, 2026, 10:14 PM UTC

   ## Impact Yealink devices running older firmware versions \(<v84\) that fetched their configurations from affected web servers \(roughly 10% of check-ins between 10/16-10/20, 100% on 10/21\) had their configurations wiped and could not reconnect to SimpleVoIP without manual intervention. The vast majority of Yealink devices are running newer firmware versions and were not affected. ## Root Cause SimpleVoIP recently replaced some of our web servers in order to keep up to date on bug and security fixes. As part of that server replacement, we introduced an unintended behavior change that redirected unrecognized URLs to our index page, whereas they would previously have received a 404. Yealink phones request some generic boot files \(e.g. /y000000000100.cfg\) before requesting their MAC-specific configurations. We supply everything via the MAC-specific config, so these generic requests are ignored. The old servers responded with a 404. After moving traffic to servers running the new OS/configuration, those requests returned HTML rather than a 404 or valid config documents. Yealink firmware versions newer than v84 ignored these responses as invalid. Older firmware versions attempted to apply the HTML response as a config, found no valid config directives within the response, and blanked the running config, including the provisioning server directive, which prevented the phones from requesting a new config from SimpleVoIP after a reboot. Factory resetting the phone would typically hit the Yealink redirect server, providing it a skeleton config with SimpleVoIP’s provisioning server URL to enable it to download its full config from us. Unfortunately, Yealink changed their redirect server infrastructure on October 1, 2025, making it inaccessible to older firmware versions and many EOL models. As a result, the same models impacted by the invalid generic config responses were unable to reconnect to SimpleVoIP without more significant effort \(providing a provisioning server URL via DHCP option 66 or manually updating phone configs individually\). ## Remediation ### Immediate Our infrastructure team updated the running web server configs to respond with 404s to the generic config requests from these phones at around 6pm CDT Wednesday. This allowed the phones to boot normally when pointed to our provisioning server. ### Near- to Mid-term We will be updating firmware for these older devices to the latest firmware versions available. Some, like the SIP-T29G or SIP-T42G, never received a firmware release from Yealink that would have prevented this issue or allowed them to recover with a one-touch factory reset. Our Operations team will discuss replacement of these models with phones that are still receiving manufacturer updates. It is common to encounter network issues \(usually firewall\) that may prevent phones from pulling the firmware we define in the device config. We’ll be making a concerted effort to notify customers proactively about devices that aren’t updating and working with them to get as close to 100% compliance as possible. Our Engineering team will also be implementing some anomaly tracking within our monitoring system focused on config requests so that we can proactively detect any sudden changes to config retrieval. ## Incident Timeline 2026\.10.16 17:00 UTC - Affected servers were entered into the available server pool serving a small percentage of config traffic. Bulk of traffic still handled by legacy servers. 2026\.10.17-10.20 - Isolated reports of devices not coming up after check-in. 2026\.10.21 05:00 UTC – Newer web servers take all traffic from legacy server pool, increasing percentage of requests handled by affected server. 2026\.10.21 23:00 UTC – Web servers are reconfigured to respond with 404s for generic config requests, allowing successful device config fetches.