The Sony Xperia S, Acro S and Ion devices were released at the beginning of 2012, and were the first line of phones to bear the Sony brand name. In this way, they were quite iconic, as they represented the end of an era of Sony Ericsson, and the beginning of Sony Mobile. And they started off on the right foot as well, adding the Xperia S AOSP as an experimental device, a tradition which sees us through the last couple of years. However, official software support for these three devices were later dropped after 18 months, with after-market developers taking them under their wing.
With this said, the Xperia S, Acro S, and Ion can now run Android 5.0 Lollipop thanks to these developers, namely Forum Member mickybart for the former, and XDA Recognized Developer BPaul for the latter two. Lollipop on the Xperia S comes in the form of a custom ROM called nAOSP (which stands for “near AOSP”) and basically comprises of AOSP with some additional features. The ROM seems to be in quite good working order with features such as GSM, WiFi, Bluetooth, GPS and the camera fully functional among others.
Android 5.0 on the Xperia Acro S and Ion are also in the form of AOSP ROMs, but it should be noted that the ROM for the Xperia ION is “devs only” and is most likely not ready to be used as a daily driver, or at least has a few problems yet to be ironed out. BPaul also convenient provides downloads of flashable ZIP packages which provide root access, CWM and TWRP, and Google Apps.