[dleslie]

> > Encrypted Index

This is not the same as the content.

[drdaeman]

Well, the client has to fetch message once, decrypt it, and upload updates to the index (kept on server).

I guess, it is a reasonable sacrifice for privacy, unless you want searches to be able to search within attachments including documents in big archives.

[Groxx]

It's still likely too large to really consider for mobile use, but yes - far better than downloading everything.