If you find the 4MB download limit of horde annoying, it is pretty simple to fix.
This assumes some knowledge of SSH. Don't try this if you are not comfortable editing files, because if you mess the formatting up, you will mess up horde.
1. Log in to ssh:
2. su to root or use sudo if you have it set up:
3. Go to the following directory:
4. Edit conf.xml using your preferred editor (I use vi) and under Fetchmail Settings change:
4000000 to what ever you want. I set mine to 15000000, but that is up to you.
You could set it to 0 if you wanted, but that could lead to issues, so I wouldn't recommend it. Save your changes.
5. Edit conf.php and change the line
vi conf.php $conf['fetchmail']['size_limit'] = 4000000;
to the same as you set in step 4. Save your changes.
6. Go to:
7. edit php.ini and make sure the value memory_limit is at least twice the value you set in steps 4 and 5. Save your changes if necessary. Default seems to be 128MB, so you are fine unless you set your mail size to 64000000 or bigger in steps 4 and 5.
8. Log out of Horde and back in again and your new download limit should be working. Remember to check these after each upgrade as Excito's scripts may set these back to defaults.
If you want to display HTML inline, instead of an attachment, edit /etc/horde/imp4/mime_drivers.php and set html inline to true and restart as above. This will be a very small hit to the normal performance, so be warned.