Sony has just certified a new Android 4.3 firmware build for the Xperia SP (C5302, C5303, C5306) with build version 12.1.A.0.266. This follows on from the previously certified build of version number 12.1.A.0.263. Sony has said that the Android 4.3 firmware update for the Xperia SP will arrive at the latest by “early February”, so this certification will tie in with that. However, this is the third Android 4.3 certified build for the Xperia SP, fingers crossed it ends up being the final build before release.
Thanks Aadi and shhshs!