This seems to be unmaintained, here is an alternative

[Foosec]

https://github.com/xhit/go-simple-mail

[DeedleFake]

It's not just unmaintained. The main developer, @alexcesaro, seems to have completely disappeared back in 2016. He suddenly stopped committing to repos despite lots of activity leading up to it, and he also stopped posting to his admittedly already inactive Twitter account.

I hope he's alright.

[fredmenez]

Maintainer has left this world, details in #182.

[Neustradamus]

Dear all, it is possible to change your code?
Change from here:

• https://github.com/go-gomail/gomail
• Where to Report Vulnerabilities? #188
• https://github.com/go-mail/mail
• https://github.com/Shopify/gomail
• Where can I report vulnerabilities? Shopify/gomail#59
• https://github.com/ory/mail

It has been unmaintained and maybe one or more vulnerabilities :/

There are:

• https://github.com/xhit/go-simple-mail from @xhit
• https://github.com/wneessen/go-mail from @wneessen

Linked to:

• Maintainer has left this world #182
• This seems to be unmaintained, here is an alternative #163
• Project unmaintained #142
• == Active Forks == #108
• The maintainer is missing.  #104
• ### Forked to github.com/go-mail/gomail ### #105
• New Release Please #94
• why the master code not updated? go-mail/mail#78
• Fork? go-mail/mail#73
• Project maintenance state go-mail/mail#61