It was brought to our attention that the Android SDK is now being released under an overall proprietary software license. In the past, we already had to release a free software SDK, back in Replicant 2.2 times, because the Android SDK was shipping with the non-free Google APIs. More recent SDK updates made these APIs only plug-ins that weren't shipped with the SDK and it was made clear that these components were non-free while all the license files we could find on the Android SDK package were free software licenses.
However now Google decided to put an overall non-free license for the SDK, which brings back the need of having a fully free Replicant SDK. Since our only SDK release is getting old (it was API level 8), we built an SDK package from Replicant 4.0 sources, that is API level 15.
You can download the SDK from the ReplicantSDK page, find an installation and usage guide as well as the build instructions on the wiki.