Unrelated to other dovecot specific questions...
Is there an index file that dovecot-lda updates for imap?
Yes. Which would be the advantage of using dovecot deliver, directly or called from procmail.
Can I just eliminate it entirely and just have procmail do all the delivery?
Yes, you can.
In fact, that's what I usually still use. Procmail can just do much more than sieve. And procmail doesn't scare me as much as sieve. But then again, I like Perl... And I've never yet encountered a problem with dovecot IMAP updating indexes on the fly -- which it does, unless deliver does it incrementally.
However, wasn't your original question about converting procmail recipes to sieve? (Yes, it was.) So what would hold you back of just not converting?
Yes, because I hadn't realized it was possible to still use procmail at all.
I had said previously, although possibly not clearly, that I'd prefer to use continue to use procmail -- sieve looks entirely too convoluted, and I just don't need to do mail filtering frequently enough to have the time to figure out sieve. It also didn't support a few other things I'm currently doing with procmail.
I can't figure out why "deliver -m" doesn't work as expected. It just doesn't create the mailbox.
Should I just use 'c' with procmail to make a copy to forward on to deliver?
DELIVER=/usr/libexec/dovecot/deliver :0 { :0c * ^X-Spam-Status xspamstatus
:0
| $DELIVER}
There has to be a better way...
Thanks, Alex