MCUpdater (MCU) is a Minecraft modpack patcher and launcher that allows server owners to build custom modpacks without having to deal with some big 3rd party’s restrictions (Tekkit, Curse, FTB, etc…). You can put whatever you want in the pack, we don’t care. That’s how it should be, you don’t have to run (for example) DW20’s exact modlist on your server if you don’t want to. It’s your server, after all.
MCU calls packs Serverpacks because they’re usually associated with and tailored to a specific server. Serverpacks are defined in XML and tell MCU where to download each individual mod and config file and how to install them. This means (among other things) that when you update your pack, the players don’t have to re-download the whole thing, just the parts that have changed.
MCU is written in Java, and is tested to work on Windows, OSX, and Linux clients. Anywhere you can run the PC version of Minecraft, you should be able to use MCUpdater.
That said, MCU is not for novice server administrators. You must build and provide web hosting for your own pack XML. There is a good community of helpful users on IRC (esper.net) at #MCUpdater where you can find additional help if the information you need is not available on this website.
Source code is available at https://github.com/MCUpdater/, where we are very willing to accept PR’s. MCUpdater is split into multiple projects and the underlying pack functionality can be used by third-party applications.