Sinch will not accept Transport Layer Security (TLS) 1.0 or TLS 1.1 versions for incoming SMTP connections to enforce use of TLS 1.2 or higher from 18-Oct-2023. TLS 1.2 provides strong protection for data sent between client and server.
This is applicable to the unsubscribe notifications; if the recipient's ISP (like Gmail, Hotmail, Yahoo, etc.) or email Client (like Microsoft Outlook, Mozilla Thunderbird, Apple Mail, etc.) do not enable/use TLS 1.2 or higher, you will no longer receive unsubscribe notifications from 18-Oct-2023.
Shahzad Ismail
Head of Knowledge Management and Community Engagement, Sinch
