0.49.5 server changes the way sales tax is calculated, so it is worked out on the price of the individual item rather than the total cost of the transaction. (So that a 1s item with 5% tax would have no tax applied (coz 5% of 1s is less than 1d) whatever amount of the item was purchased. )
Though this is a little more limiting, and means sales tax is only applied to the more expensive items, it is more consistent and does avoid the silly situation where ppl would end up buying small amounts repeatedly to avoid paying tax.