I don't know the exact number in terms of value (it likely depends on the market price of STEEM), but what was done is to convert the dust vote threshold where votes would previously have been rejected altogether, into a deduction where you can still vote but it doesn't have any effect on reward.

Any vote that you would have been able to make at all (without it being rejected with an error message) prior to this update does count. Votes that would have been rejected altogether before are now accepted as "vote only" (no reward).

EDIT: I looked in the developer discussion and it seems the threshold was estimated at something like 0.0001 STEEM. This affects truly tiny votes, not most merely small ones below 0.01 reward.