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Release Notes

Release Notes for Teler across the API, SDKs, webhooks, and platform, newest first. Each entry is grouped by month and tagged by change type.

September 2026

September 18, 2026Stable SDK releases

Stable releases of the Teler SDKs with complete API coverage and production-ready improvements.

Added
  • Node SDK 2.0.0 - Stable release with full API support for voice calls, SIP trunks, virtual numbers, recordings, events, and secrets management. All features are production-ready.
  • Python SDK 1.0.0 - Stable release with sync and async clients, comprehensive API coverage for all Teler services, and full feature parity with the Node SDK.
August 2026

August 21, 2026IP Access Control List (ACL)

SIP Trunks can now be secured with IP Access Control Lists, restricting which IP addresses are allowed to send traffic to a trunk. A single ACL can be assigned to multiple SIP Trunks.

Added
  • IP Access Control Lists. Create an ACL made up of allowed IP addresses or CIDR ranges, and assign it to a SIP Trunk to restrict which sources can send SIP traffic to it.
  • Reusable ACLs. A single ACL can be assigned to multiple SIP Trunks, so shared allowlists (e.g. a PBX or AI provider’s IP ranges) don’t need to be duplicated per trunk. Manage IP ACLs via the REST API or SDK. See SIP Trunking for SDK examples, and the API Reference for REST parameters.

August 2, 2026SIP UDP support

Support for SIP UDP transport.

Added
  • SIP UDP transport. SIP trunks can now connect over UDP, in addition to TCP/TLS.
  • Credential-based authentication only. IP-based authentication is not available over UDP — trunks must authenticate with credentials. See SIP UDP
July 2026

July 24, 2026Python SDK updates

Python SDK 0.2.1 and 0.2.2 with bug fixes and API migration.

Fixed
  • Dial response field - Fixed typo in 0.2.1: from_numbre renamed to from_number.
Changed
  • Voice calls endpoint migration - Updated in 0.2.2: Migrated to new endpoint https://api.frejun.ai/api/v1/voice/calls/initiate. The deprecated endpoint https://api.frejun.ai/api/v1/calls/initiate is no longer supported.

July 20, 2026Node SDK 1.0.10

Node SDK 1.0.10 with API endpoint migration.

Changed
  • Voice calls endpoint migration - Migrated to new endpoint: https://api.frejun.ai/api/v1/voice/calls/initiate. The deprecated endpoint https://api.frejun.ai/api/v1/calls/initiate is no longer supported.

July 16, 2026Node SDK 1.0.9

Node SDK 1.0.9 with bug fixes and API improvements.

Fixed
  • Play flow action - Fixed parameter name: file_url renamed to media_url for consistency with API contract.

July 11, 2026Call transfer (agent-to-human handoff)

Transfer an in-progress call to a new PSTN or SIP destination, so an automated agent can hand the caller off to a live person.

Added
  • Transfer control operation. POST /api/v1/voice/calls/{id}/transfer, async and idempotent (Idempotency-Key required). Cold transfer to a pstn or sip target, with timeout, record, ringback, and an on_failure fallback. See Live call control.
  • Transfer lifecycle events: call.transfer.initiated, call.transfer.bridged, call.transfer.failed. See Call events.
  • transfer flow verb for initiating a transfer directly from a call flow document (initiated_by: "flow").

July 3, 2026Webhook version 2026-06-01

A new dated webhook version, 2026-06-01, opt-in per Voice App or SIP Trunk. The previous 2025-08-01 version is unchanged and continues to work for existing pins.

Added
  • Event envelope. Every webhook body is now wrapped with id, type, api_version, occurred_at, account_id, voice_app_id / sip_trunk_id, call_id, leg_id, and data. See Event envelope.
  • New headers: X-Teler-Event-Id, X-Teler-Api-Version, X-Teler-Source.
  • Resource-typed IDs: acc_, va_, st_, cs_, cl_, ms_, evt_, rec_, pb_.
  • New events: leg.created, leg.answered, leg.completed, stream.initiated, stream.completed, recording.completed, recording.failed.
  • Call resources API. GET /api/v1/voice/calls, GET /api/v1/voice/calls/{id}, GET /api/v1/voice/calls/{id}/legs, and the SIP-trunk equivalents under /api/v1/sip/calls. See Call resources.
  • Live call control. POST /api/v1/voice/calls/{id}/hangup / mute / dtmf / play, async and idempotent (Idempotency-Key required). See Live call control.
  • dial flow verb. Originate an outbound leg and bridge it into the current call, with recording modes, custom SIP headers, and per-outcome fallbacks (on_no_answer, on_busy, on_failure).
  • Stable event id across retries, replays, and recovery re-deliveries, for idempotent dedupe. See Retries and idempotency.
Changed
  • Field renames inside data: hangup_time to ended_at, hangup_source to ended_by, duration (seconds) to duration_seconds, and answer_time to answered_at. New normalized reason field. (direction is unchanged — inbound / outbound on both versions.) Full field-level diff and migration steps: API versioning.
May 2026

May 20, 2026SIP user support in Inbound SIP URL

Inbound SIP URLs now support a custom SIP user in place of a number, for platforms that identify calls by username rather than phone number.

Added
  • Custom SIP user in Inbound SIP URL. Inbound SIP URLs now accept the format sip:sip_user@sip_url:port, alongside the default sip:number@sip_url:port. The sip_user (or number, in the default case) is used by the AI platform for call identification purposes. See SIP Trunking → Inbound routing.
January 2026

January 30, 2026Webhook signing secrets

Webhook requests can now be authenticated using a per-endpoint signing secret, verified via HMAC. Existing unsigned webhook configurations continue to work.

Added
  • Webhook signing secret. Generate a secret per Voice App or SIP Trunk webhook endpoint to enable request authentication.
  • Signature headers: X-Teler-Timestamp (event timestamp for replay protection) and X-Teler-Signature (HMAC-SHA256 digest computed over the timestamp and raw request body using the endpoint’s signing secret).
  • Signature verification. Validate incoming webhook requests are genuinely from Teler and haven’t been tampered with in transit. See Signing & verification.