First of all, there is no Premiere Plus package. Those are two different packages with different costs and limits.
But what you booked is what you will get, not the new enhancements unless you pay to upgrade to the new pricing.
Note, for example, that if you booked the Plus package at $40 or $50 a day (depending when you booked), the package covers all beverages that are priced up to $12. It does not promise specific beverages, so if Princess increases the pricing for beverages that were $12 or less to where they are now higher than $12, they are not covered without paying extra.