foldername
When using SET FOLDER, specifies the name of the folder from
which messages will be selected.
If you omit the folder name when specifying SET FOLDER, the
folder used is determined in the following order:
1. The current folder is used, if any (unless the /NEW qualifier
is specified).
2. The NEWMAIL folder is used if:
o You specify the /NEW qualifier.
o You omit selection qualifiers and you have new mail.
3. The MAIL folder is used.