That is a good news.
And for people who think Arc cannot run ICS because of less RAM including Sony, please have a look at HTC one V.
People were arguing that as nexus s runs on stock ASOP ICS, it is not laggy.
But see, HTC one V despite of 1Ghz single core processor and 512mb ram is capable of running ICS smooth with HTC SENSE 4.0 (ram eater)
Sony please no excuse now. And please update kernal.
SONY Xperia ZL