MeF Processing Year Messages Transmitters and Software Developers Tax Return Preparers Modernized e-File Business Rule (BR R0000-198) Modernized e-File Business Rules IND-664, IND-665, IND-666, IND-667 or IND-672 MeF Working Group Meetings States and external partners are encouraged to attend the MeF Working Group meetings to keep updated on the status and changes to the MeF Program. MeF Working Group meetings are generally held once a month. If you would like to receive a calendar invite for the meetings, please send your Name, Company Name and e-mail address to the MeF Mailbox with a request to be added to the MeF Working Group Meeting distribution list. MeF Program Information Page