What we already know and Sony Ericsson — to be called only Sony after mid-2012 — emphasized many times in the past is that its entire Xperia line-up from this year will receive official Android 4.x Ice Cream Sandwich updates. What we don’t know is when exactly this will happen, with some indicating March and others pointing towards a sooner date, in January.
What appears to be Ice Cream Sandwich firmware updates for the Sony Ericsson Xperia arc and neo have been found online over at PTCRB. They are reportedly under certification and chances are other ROMs for other devices in the Xperia line-up have also been submitted. If Sony Ericsson is quick to act on the updates it might offer the refresh ahead of some other big guns like Samsung — who already have the code since it makes the Galaxy Nexus — HTC or LG (who both confirmed upcoming updates for certain phones without making a reference date public).
Update: According to Xperia Blog, the two firmwares are not Ice Cream Sandwich but NTT DoCoMo Japan branded ROMs (thanks Frank!)