For messages no, for attachments yes. WildDuck parses stored messages and separates attachments from rest of message data. Deduplicated attachments are then sto

For messages no, for attachments yes. WildDuck parses stored messages and separates attachments from rest of message data. Deduplicated attachments are then stored to MongoDB as GridFS files but this could be just as well S3 in the future. Message data needs to be in Mongo because of indexing and speed, attachments do not have such requirements and could be stored anywhere.