Known issues & limitations

Current limitations and known issues in Conduit.

Privacy & policy constraints

Background GPS tracking not supported

Status: Limitation of the current release

Reason: Conduit does not ask for "Always" location permission, and iOS can suspend an app in the background at any time.

Current behavior:

GPS publishes while Conduit is in the foreground
With Settings → Publishing → Background Publishing off, GPS stops when you leave the app
With Background Publishing on, GPS may keep publishing for a while, but iOS can suspend Conduit at any time, so do not rely on it for a long track

Workaround:

Keep the app in the foreground during GPS data collection

Platform limitations

macOS: No IMU/GPS sensors

Status: Hardware limitation

Reason: Macs have no accelerometer, gyroscope, magnetometer, barometer, ambient light sensor, GPS, proximity sensor or LiDAR that Conduit can read.

Available on Mac (Mac Catalyst): Camera, Microphone, Battery, Thermal and Game Controller. IMU, Magnetometer, Barometer, Illuminance, GPS, Proximity, LiDAR and Device Pose are not available.

Use case: Mac camera, microphone and game controller input, and development/testing. See Platform notes.

iOS restrictions

Camera/LiDAR stop in background

Status: iOS system restriction

Reason: iOS doesn't allow camera/ARKit usage in background. Camera and LiDAR stop even with Background Publishing on. The Microphone also stops in the background in the current release.

Workaround: Keep app in foreground when using Camera, LiDAR or Microphone

Proximity sensor only on iPhone

Status: Hardware limitation

Reason: iPads don't have proximity sensors.

Workaround: Use iPhone for proximity sensing, or use LiDAR for distance measurement

Performance & stability

Multiple cameras may cause memory warnings

Status: Known issue

Behavior: Enabling 3-4 cameras simultaneously may trigger iOS memory warnings.

Mitigation:

On a memory warning, Conduit stops all cameras and LiDAR
Reduce number of active cameras
Lower the camera's Resolution in its settings

Workaround: Enable only cameras you need

High frame rate may cause thermal throttling

Status: Expected behavior

Reason: Continuous 100 Hz IMU + multi-camera can heat device.

Mitigation:

iOS will throttle CPU/GPU when too hot
Rates may automatically decrease

Workaround:

Reduce publishing rates
Disable unused sensors
Allow device to cool between sessions

Network & connectivity

Initial connection can be slow

Status: Normal behavior

Reason: Opening the Zenoh session or DDS participant and creating a publisher for each sensor can take a few seconds. Conduit retries each initial connect up to 3 times before it reports "Connection Failed".

Workaround: Wait for "Publishing" state before expecting data

Connection lost not always detected immediately

Status: Known limitation

Reason: A router or host that goes away is noticed only when a send fails.

Behavior: Data can stop for a while before Conduit notices. Once a send fails, Conduit reconnects in the background: it retries after 1, 2, 4, 8 and 16 seconds, then every 30 seconds, with no limit. If the device loses its network entirely, Conduit stops publishing and shows Connection Lost.

Workaround: Wait for the next retry, or stop and start publishing. See Connection drops and reconnects.

Wire format compatibility

rmw_zenoh_cpp version sensitivity

Status: By design

Reason: Wire format changes between rmw_zenoh_cpp versions.

Mitigation:

Settings → Distribution: Humble, or Jazzy / Kilted / Lyrical / Rolling (one shared wire format)

Known compatible versions:

ROS 2 Humble: rmw_zenoh_cpp (Humble release)
ROS 2 Jazzy: rmw_zenoh_cpp (Jazzy release)
ROS 2 Kilted: rmw_zenoh_cpp (Kilted release)
ROS 2 Lyrical: rmw_zenoh_cpp (Lyrical release)
ROS 2 Rolling: rmw_zenoh_cpp (Rolling)

Workaround: Set Distribution to match the host.

DDS transport

Camera/LiDAR fragmentation loss on DDS over WiFi

Status: Known limitation

Reason: Large RTPS messages (>1400 bytes — camera, LiDAR, CameraInfo with large K matrices) are split into UDP fragments. Consumer WiFi often drops or reorders fragments, especially over multicast.

Mitigation:

Add peers in Settings → Discovery → Peers, and add the iPhone's address as a peer on the host. With peers, Conduit sends over unicast on top of multicast.
Reduce camera resolution, or turn on LiDAR point cloud compression.
Use wired Ethernet on the ROS 2 host if possible.

CameraInfo requires BestEffort subscriber QoS

Status: By design

Reason: CameraInfo publishes with BestEffort + TransientLocal QoS (latchedBestEffort) to match DDS behavior on iOS. Standard image_transport subscribers default to Reliable, which does not match.

Workaround: Override the subscriber QoS:

ros2 topic echo /conduit/camera/front/camera_info \
  --qos-reliability best_effort \
  --qos-durability transient_local

Disconnect delay on DDS

Status: Expected behavior

Reason: Closing the DDS publishers and the DDS participant takes some time.

Behavior: After you press Stop, it can take a few seconds before the app fully releases the domain. No action is needed.

DDS requires WiFi — no cellular fallback

Status: By design

Reason: DDS discovery binds to a specific network interface (en0 on iOS). Cellular or VPN interfaces are not supported; multicast/unicast discovery requires the device and the ROS 2 host to be on the same LAN.

Workaround: Use the Zenoh transport if you need to cross networks, for example over Tailscale (see Connect with a QR code) or with a router address you can reach.

Premium features

Premium purchase required for some sensors

Status: By design (business model)

Free:

IMU, GPS, Magnetometer, Barometer, Illuminance, Proximity, Battery, Thermal, Microphone
Front camera
MCAP recording to the device

One-time In-App Purchases:

Back Cameras — Wide, Ultra Wide and Telephoto cameras in one purchase
LiDAR
Game Controller
Background Mode — keep publishing while the app is in the background
Recording Export — export and share recorded .mcap files

Premium purchases not syncing

Status: Rare issue

Reason: App Store receipt verification delay.

Solutions:

Restart app
Restore purchases (Settings → Premium Features → Restore Purchases)
Verify Apple ID is correct

Workaround summary

Issue	Workaround
Background GPS	Keep app in foreground
macOS no IMU / GPS	Use iPhone/iPad
Camera background	Keep app in foreground
Memory warnings	Reduce active sensors
Thermal throttling	Lower rates, fewer sensors
Connection slow	Wait for "Publishing"
Connection drops	Wait for the automatic reconnect
DDS fragmentation loss on WiFi	Add discovery peers on both sides; lower camera resolution or compress LiDAR
CameraInfo QoS mismatch	Subscriber: `--qos-reliability best_effort --qos-durability transient_local`
DDS disconnect delay	Expected behavior — no user action required
DDS over WAN / cellular	Use Zenoh transport with a public router instead

Reporting new issues

Found a bug not listed here? Create an issue with:

Platform and OS version
Sensor type affected
Steps to reproduce
Expected vs actual behavior

Feature requests

Want a new feature? Request it here

We prioritize based on:

User impact
Technical feasibility
Platform constraints
Development resources