Alternative SMTP server integrations

Before implementing my own SMTP module for Magento 2 I have tried a lot of alternatives.

1. Mageplaza SMTP Extension

It will spam you:

  • via built-in Magento backend notifications
  • via email (the extension requires email registration)

2. MagePal Smtp App

It just does not work for me: I have got a lot of PHP errors.
It looks like the extension is built for an outdated Magento 2 versions despite the last commit was just a day ago.
Maybe MagePal developers do not test their extension with all Magento 2 versions?

What issues were you having with MagePal extension?