Gmail, Exchange and iCloud mail all seem to fall back on plaintext when TLS is unavailable. Apparently gmail displays hazard icons in the UI if an email isn’t

Gmail, Exchange and iCloud mail all seem to fall back on plaintext when TLS is unavailable. Apparently gmail displays hazard icons in the UI if an email isn’t sent over TLS. I’ve not found precise documentation about Thunderbird’s behaviour. https://workspaceupdates.googleblog.com/2020/04/improve-email-security-in-gmail-with-TLS.html?m=1 https://workspaceupdates.googleblog.com/2020/04/improve-emai... https://support.apple.com/en-gb/guide/security/sec100a75d12/web https://support.apple.com/en-gb/guide/security/sec100a75d12/... https://learn.microsoft.com/en-us/purview/email-encryption https://learn.microsoft.com/en-us/purview/email-encryption