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# Trailer vehicle association modified

POST 

Emitted when a trailer-vehicle association is modified in our database.

e.g. The record fetched from the TSP is different from what we had stored in our database and it prompted us to update the existing record.

Reference: https://catena.ferndocs.com/api-reference/notifications/webhook-events/trailer-vehicle-association-modified

## Request

### Payload

- `version` (string, required) — Version of the schema used for this event
- `data` (list of BaseTrailerVehicleAssociation, required) — The event payload, with one or more records of the specified type
- `webhook_id` (string, required) — Unique identifier for the webhook subscription that triggered this delivery
- `event_name` (string, optional, default: trailer_vehicle_association.modified)
- `timestamp` (datetime, optional, nullable) — ISO 8601 timestamp when the event occurred
- `id` (string, optional, nullable) — Unique identifier for this specific event instance (UUID v7 for time-ordered sorting)
- `delivery_attempt` (integer, optional, default: 0) — The number of times the event has been attempted to be delivered

## Types

### BaseTrailerVehicleAssociation

Base trailer-vehicle association event.

- `id` (string, required) — Internal unique identifier for the telematics event record (Catena PK).
- `fleet_id` (string, required) — The Catena fleet this record belongs to (multi-tenant scope).
- `fleet_ref` (string, required, nullable) — The reference of the fleet in the partner system
- `source_name` (enum, required) — The underlying telematics platform that provided this data (e.g., `samsara`, `motive`, `hos247`). Note: Some platforms like `hos247` offer white-labeling, so multiple TSPs may share the same source_name — use `tsp_id` or `tsp_slug` to identify the specific ELD provider.
  - Allowed values: `ada`, `ai_eld`, `air_eld`, `alfa_eld`, `alpha_eld`, `als`, `anytrek_pro`, `anytrek_classic`, `apex_eld`, `apollo`, `apollocloud`, `ascend`, `att`, `awaregps`, `azuga`, `bigroad`, `bluehorse_eld`, `blueinktech`, `bouncie`, `budgetgps`, `catena_simulator`, `captain_eld`, `carrier_lynx`, `chronos`, `club_eld`, `cogo_eld`, `counting_trucks_eld`, `cyntrx`, `digital_eld`, `dragon_eld`, `dreyev`, `drive_hos`, `drive_hos_v2`, `driver_tech`, `dsg_elogs`, `dynamic_eld`, `eighteighteight_eld`, `eld_88`, `eld_books`, `eld_mandate`, `eld_mandate_prime`, `eroad`, `eva_eld`, `evo_eld`, `expressway_eld`, `extreme_eld`, `ezlogz`, `ez_lynk`, `factor_eld`, `firstgate`, `fleetcomplete`, `fleetcompletehub`, `fleethunt`, `fleetpulse`, `fleetsharp`, `fleetup`, `fm`, `fordpro`, `forwardthinking`, `forza_eld`, `geotab`, `gpsinsight`, `gpstab`, `gpstrackit`, `grand_eld`, `greenlight`, `groundhog`, `hcss`, `hos247`, `hutch`, `intellishift`, `ironman_eld`, `isaac`, `jjkeller`, `kinexaiot`, `knight_eld`, `konexial`, `lioneight`, `linxup`, `loop_eld`, `lucid_eld`, `luna_eld`, `lytx`, `lytxv3`, `mapon`, `matrack`, `maven`, `mdm_eld`, `michelin_connected_fleet`, `mobilefleet`, `moonlight_eld`, `motion_eld`, `motive`, `my_drivebook`, `my_logs_eld`, `nero`, `netradyne`, `new_eld_world`, `nextgen_eld`, `nextraq`, `nexus_eld`, `omnitracs`, `1sew_eld`, `onestep`, `ontime_eld`, `optima`, `optimus_tracker`, `orbcomm`, `orient_eld`, `ozod_eld`, `panda_eld`, `patriot_eld`, `payd`, `peak_eld`, `pedigree`, `peoplenet`, `phillips_connect`, `phoenix`, `pop_eld`, `prologs`, `proride_eld`, `qualitylogs_eld`, `randmcnally`, `rastrac`, `raven`, `redfox`, `regulog_eld`, `ridehub`, `rigbot`, `roadeazy`, `roadready`, `rock_eld`, `rollingtrans`, `routemate`, `route_one_eld`, `royal_eld`, `safelane`, `samsara`, `selectivedrive`, `simba_eld`, `skybitz`, `smart_elds`, `sparkle_eld`, `spireon`, `sts_eld`, `sun_eld`, `surfsight`, `swift`, `switchboard`, `synergy_eld`, `teletracnavman`, `teletracnavman_director`, `telogis`, `tenna`, `teslemetry`, `thermo_king`, `think`, `tive`, `topcompliance_eld`, `traccar`, `trackease_eld`, `trackpro`, `traclog`, `transflo`, `trimac`, `trimble`, `truckford`, `truckspy`, `truckx`, `trueroad_eld`, `tt`, `txt_eld`, `us_fast_eld`, `verizon_connect`, `vista_eld`, `vistracks`, `vlog_eld`, `vulcansols_eld`, `wialon`, `webfleet`, `wizefleet_eld`, `xplore_eld`, `zigzag_eld`, `zms_eld`, `zonar`, `zubie`
- `connection_id` (string, required) — The specific fleet↔TSP connection through which this record was sourced.
- `source_id` (string, required) — The ID of the record in the TSP or a deterministic ID/Hash generated from a composite unique key
- `created_at` (datetime, required) — Immutable: first time this record was ingested into our system.
- `updated_at` (datetime, required) — Last time we modified this record in our system.
- `occurred_at` (datetime, required) — When the underlying event/observation occurred, as reported by the TSP, or the moment it was ingested by us if not available.
- `tsp_id` (string, optional, nullable) — Unique identifier of the TSP at Catena Telematics from which this record was ingested.
- `tsp_slug` (string, optional, nullable) — Human readable slug of the TSP at Catena Telematics from which this record was ingested.
- `deleted_at` (datetime, optional, nullable) — Logical delete marker: when the TSP stopped reporting this record.
- `execution_id` (string, optional, nullable) — Identifier for the ingestion execution that processed this record (for tracing).
- `schedule_id` (string, optional, nullable) — Identifier for the ingestion schedule that triggered this record's processing (for tracing).
- `extras` (map from string to any, optional, nullable) — Additional data available in the TSP (e.g., we may have `external_id`, `provider_resource_id`, etc. — this field captures all those extra attributes in a flexible way).
- `trailer_id` (string, optional, nullable) — Internal trailer identifier (Catena FK).
- `vehicle_id` (string, optional, nullable) — Internal vehicle identifier (Catena FK).
- `source_trailer_id` (string, optional, nullable) — External source system trailer identifier (from the TSP).
- `source_vehicle_id` (string, optional, nullable) — External source system vehicle identifier (from the TSP).
- `trailer_sequence` (integer, optional, nullable) — Sequence number or position of the trailer attached to the vehicle.