Fixes composer dependencies: Package phpunit/phpunit-mock-objects is abandoned
We cannot support v8 yet because of errors like:
Declaration of MailFunc::setUp() must be compatible with PHPUnit\Framework\TestCase::setUp(): void
It would require dropping PHP < 7.1 support.
We sometimes get broken character encodings such as:
Subject: =?iso-2022-jp?B?GyRCLWo7M3l1OSk2SBsoQgo=?=
This actually is not a strict ISO-2022-JP string, but a CP50220 string
that is a variant of ISO-2022-JP with extended characters proposed by
Microsoft. Iconv can not handle these encodings well.