- implement managemails.forms.ChangeMailboxPasswordForm
- extract code for determining hosting package and customer from URL into
HostingPackageAndCustomerMixin
- implement managemails.views.ChangeMailboxPassword
- add new URL pattern 'change_mailbox_password' to managemails.urls
- add template managemails/mailbox_setpassword.html
- link from template hostingpackages/customerhostingpackage_detail.html to
change_mailbox_password
- add german translation for new strings
- document new feature in changelog
