There are loads on new configuration options, too many for me to list all of them here. Here are some new and some that have changed, though:

• VISIBLE_ADMINS makes Kareha mark those who post with a tripcode that's listed in ADMIN_TRIPS (capcodes, essentially).
• FAVICON lets you specify where Kareha looks for its favicon.
• DISPLAY_ID and SILLY_ANONYMOUS now give you much more control over how the ID code is generated. The can contain any of the words "day", "thread" and "board" to make ID codes unique per day, thread or board. The default is now "thread board" instead of "day", which means that ID codes stay constant inside a thread as time goes on, but differ between threads and boards. To disable the "Heaven" ID, leave EMAIL_ID empty.
• PAGE_GENERATION selects how pages are generated. "single" is the old single-page mode, "paged" is futaba-style, and "monthly" make a single frontpage like "single", plus pages for each month. The last one is for blogs, obviously, but I have yet to make a blog mode.
• DELETE_FIRST lets you decide what to do when the first post in a thread is deleted.
• The old Futallaby/Wakaba options SHOWTITLEIMG etc are now implemented in Kareha too, both for message and image board mode.
• Some new old thread deletion modes: MAX_POSTS and MAX_MEGABYTES that act the same as the Wakaba options of the same names. Limit the number of posts, or the image disk space usage of the board.