As far the information provided by Sony Developer blog, it seems that Xperia Ray and other Sony Ericson 2011 Models which were said to be getting the ICS 4.0 update on last of march/first of april will get the update on mid-april.
It seems like that Sony is finding it difficult to implement the ICS features with their XPERIA 2011 models, specially in GUI part. Thats why they have delayed the update date again for 15-20 days as they promised to be. As far the information they provided that ICS consumes more resource than Gingerbread on their 2011 Xperia models. Sony developers also hinted their Customers with one of their blog post not to upgrade to Icecream sandwich from Gingerbread. But every Xperia model owners are waiting eagerly to try ICS on their Xperia phones and sony cant make anyone not waiting for the ICS update who bought their Xperia phones just to implement the ICS UPDATE. Till then all we can do is wait and hope that Sony developers will come with a stable ICS 4.0 update for our Xperia Ray. I will be updating the blog with any new news about the ICS update that comes up.