PHPMailer 6.0.1

PHPMailer 6.0.0

5.2.24

5.5.23

Generate a warning when using a buggy PHP version, see PHPMailer#953

Merge branch 'master' into 6.0

# Conflicts:
#	examples/scripts/XRegExp.js
#	extras/htmlfilter.php

Merge remote-tracking branch 'origin/master'

v5.2.21

Fix missed version number update

Fixed link to Security (PHPMailer#931)