When we talked to Sony Ericsson for the Xperia X10 for AT&T review, reps informed us that the phone is upgradeable but no further information could be provided. Now, we can't say if this latest bit is global or just for those across the pond, but the official Twitter account of SE's UK arm wrote today that Android 2.1 is "due for release before the end of September this year." Certainly a step up from the Q4 2010 time frame we heard previously, but again, we've no clue if this applies to the US as w