This project effectively died in 2017. The lead developers admitted that reverse engineering the game's network stack was impossible without EA's source code. Do not waste time searching for this; you will find ghost forums and broken API links.
The current iteration of the (often referred to as the S3MP or built upon the architecture of the SimSync concept) is a breakthrough in community engineering. Developed by a small, passionate team of modders, it utilizes a client-server architecture similar to traditional online RPGs, rather than the buggy peer-to-peer connection methods of the past. The Sims 3 Multiplayer Mod