In general, none of the MailChimp tags will work because they specifically relate to a MailChimp list or integration, which is not accessible by Mandrill. In general, merge tag values should be provided in the API call or SMTP headers since Mandrill processes those on a per-message basis. As you discovered, there are some that may work, but it's generally best not to rely on that working, and instead provide values for things you want to merge in. Right now, the year will work, as will the DATE tag. Others to note:
*|EMAIL|*
will pull in the recipient's email address unless you provide a different value for that merge tag in the API call or SMTP headers.
If you use *|FNAME|*
or *|LNAME|*
and don't provide recipient values for the one you're using, we'll attempt to parse the name
parameter from the recipient list (the to
array) to get the recipient's first or last name. That's fairly basic, though, so if you want to include them, it's best to actually define them.