Bukkit

• 1.6.3 A lot more stuff added in this time. I'm trying to stop using the word "equation", because the word "expression" is the technical term (an equation is two expressions that are equivalent). Anyways: Added Weakness effect support. Added Strength effect support. Fixed arrow bug. Added (fixed) Critical damage support. All of that stuff is now calculated with the weapon changes (even critical damage, so it no longer has a hook). Added 3 new operators: >>, >>>, <<
• 1.5.0 I wasn't very meticulous with versions this time around. Added internal changes that allow formulas. Added fall damage support (including armor protection for falling). Added critical damage support (that is, falling and hitting at the same time). The critical damage code is in place, but I don't think it works; you're probably best off just leaving it. Restructured the program files to make more sense.
• 1.4.0 Began work on hooking the random field in net.minecraft.server.Entity. If you receive messages about research, PLEASE comment on my page, and paste the message. If you know what was happening at the time (I'm looking for critical hits), please post!
• 1.3.9 Added a permissions node, vacuum.changedamage.damage. Added potion support, but as it does not work, this was removed for this release.
• 1.2.1 Added armor support.
• 1.0.0 Moved all damage configuration to the config.yml. Added world support.
• 0.1.2 Config file now updates if it was missing any information
• 0.1.1 Moved default damage to the config.
• 0.0.8 Fixed bug with arrows when PvE was disabled.
• 0.0.7 Added arrows. Allowed debugging text option.
• 0.0.3 Default option changed ID to 0 instead of -1 to avoid a bug
• 0.0.2 Added default option
• 0.0.1 Fixed resource link
• 0.0.0 Release!

There are traces of potion support and critical support in the code. Updater doesn't work. If you figure out how to enable it, you already know what you're getting yourself into.