generated: '2026-08-04'
method: searched
source: https://github.com/Neros-Technologies/APEX
applies_to: APEX — Adaptive Payload EXchange

versioning:
  scheme: in-band protocol version byte + a jointly-versioned spec/implementation snapshot
  protocol_version_field: outer header byte 0
  current_protocol_version: V0 (protocol_version = 0)
  spec_snapshot: v0.8.0
  snapshot_source: https://github.com/Neros-Technologies/APEX/blob/main/VERSION.txt
  snapshot_rule: >-
    The specification documents and the C reference implementation are versioned
    together as one snapshot; the current version is recorded in VERSION.txt.
  status: draft
  status_statement: >-
    "Status: Draft. These specifications are under active development and may change.
    Mechanical and electrical details are still being finalized." — APEX README.
  docs: https://github.com/Neros-Technologies/APEX/blob/main/spec/APEX_Core.md

version_negotiation:
  mechanism: >-
    A device attempts DEVICE_INFO at its highest supported protocol_version first. If
    the host does not support it, the host replies ACK_REJECT_VERSION (ack = 0x03) and
    the device falls back to the next-lower version it supports.
  burden: on the device — hosts always accept the highest version they support and never request a downgrade
  session_rule: once CONNECTED at a version, every frame in that session uses that version; changing version requires a reset and re-discovery
  unknown_version_rule: a frame whose protocol_version the receiver does not support MUST be dropped without acting on its contents

deprecation:
  policy_url: null
  sunset_header: false
  note: >-
    No deprecation or sunset policy is published. The protocol is at V0 and pre-1.0, and
    the README states the specs may change. USB_FS_HUB (traffic_type 5) is reserved with
    its spec marked TBD, and two areas — passthrough/hub nodes and baud-rate negotiation —
    carry explicit "Open" markers in the spec. No `Deprecation` pointer is wired in
    apis.yml because there is no deprecation policy to point at.

status_page:
  url: null
  probed:
  - url: https://status.neros.tech/
    status: 000   # DNS does not resolve
  note: >-
    No status page. No `StatusPage` pointer is wired in apis.yml.

sla:
  url: null
  note: No public SLA. Neros sells hardware to military customers; commercial terms are not published.

device_lifecycle:
  source: spec/APEX_Core.md §4 Device Lifecycle Status
  type: ApexV0DeviceStatus_t
  scope: host-tracked, device-level; distinct from any class-specific state machine
  states:
  - value: '0x00'
    name: UNKNOWN
    meaning: No information available for this device slot (empty / recycled).
  - value: '0x01'
    name: NEW
    meaning: >-
      Provisional. The host has assigned a device_id and replied ACK_OK, but the device
      has not yet confirmed the latch. The slot is reserved, not committed; no class
      traffic flows. A NEW slot whose device never confirms is recycled.
  - value: '0x02'
    name: CONNECTED
    meaning: Device has confirmed its ID and is ready to receive class-specific commands.
  - value: '0x03'
    name: EXPENDED
    meaning: Device has signaled it is expended; heartbeat tracking may be disabled.
  - value: '0xFF'
    name: FAULT
    meaning: >-
      Device fault — missed heartbeats or another error condition. The host frees a
      FAULT slot a few seconds later so its device_id returns to the pool.
  transitions:
  - from: UNKNOWN
    to: NEW
    trigger: host assigns a device_id and replies ACK_OK to DEVICE_INFO
  - from: NEW
    to: CONNECTED
    trigger: host receives CONFIG_ACK, or any subsequent frame bearing the assigned ID
  - from: NEW
    to: UNKNOWN
    trigger: device silent for the 5 s watchdog window — slot recycled
  - from: CONNECTED
    to: FAULT
    trigger: missed 5 s heartbeat watchdog
  - from: CONNECTED
    to: EXPENDED
    trigger: device signals it is expended
  - from: FAULT
    to: UNKNOWN
    trigger: host frees the slot (recommended >= 5 s after the fault)

implementation_maturity:
  source: lib/README.md — "Scope of v1"
  complete:
  - COBS framing, CRC-16/CCITT-FALSE
  - Outer header pack/unpack
  - Host discovery + device table + lifecycle (NEW -> CONNECTED -> EXPENDED / FAULT)
  - Device discovery + 1 Hz heartbeat + 5 s watchdog
  - NAME_REQUEST / NAME_REPLY
  - HOST_STATE broadcast
  - Activation class — Device state machine + COMMAND/ACK/STATUS/CAPABILITY
  - Activation class — Host driver
  - Multi-class on a single link (host side)
  not_implemented:
  - feature: Passthrough / hub nodes
    reason: spec marks the area as not well defined
  - feature: Baud-rate negotiation
    reason: spec does not define a CONFIG message for this yet

device_class_registry_status:
  see: data-model/neros-data-model.yml
  reserved_pending_spec:
  - traffic_type: 5
    name: USB_FS_HUB
    spec: TBD

x-evidence:
  fetched: '2026-08-04'
  sources:
  - url: https://raw.githubusercontent.com/Neros-Technologies/APEX/main/VERSION.txt
    http_status: 200
  - url: https://raw.githubusercontent.com/Neros-Technologies/APEX/main/README.md
    http_status: 200
  - url: https://raw.githubusercontent.com/Neros-Technologies/APEX/main/spec/APEX_Core.md
    http_status: 200
  - url: https://status.neros.tech/
    http_status: 000