Question about ITERINDEX in 2.2.32

Hello

 I have a question about the new setting ITERINDEX. This is my 

filesystem layout

 /indices_dovecot : 8 x Fast SSD drives
 /buzones : 32x SAS 10k rpm disks
 /buzones/alternativo : 24 x SAS 7.2k rpm slow disks

 This is my mail_location:

mail_location = mdbox:/buzones/domain/%2.26Hn/%2.200Hn/%n:INDEX=/indices_dovecot/indices/%2.26Hn/%2.200Hn/%n:ALT=/buzones/alternativo/domain/%2.26Hn/%2.200Hn/%n

 What should I write in mail_location with the new ITERINDEX setting?

 Regards

 María