v2.8.0

Added

• #272 - Added support for PSR-3 compatible logging solutions and a new debug feature to log requests/responses
• #274 - Added support for the detail field on some new Voice API incoming events (https://developer.nexmo.com/voice/voice-api/webhook-reference#event-webhook)
• #273 - Added new content-id and entity-id fields to support regional SMS requirements, and a shortcut for enabling DLT on Indian-based SMS