Kurzweil often provides software updates for their keyboards, enhancing features, adding new sounds, or improving performance. Users can check the Kurzweil website for updates specific to the Proteus Portable 88.
If you can stretch your budget by roughly $50–$100, the Roland FP-10 or Yamaha P-45 are significantly better instruments in terms of key action and sound realism. However, if the Proteus is the limit of your budget, it is a capable machine to start your musical journey.
If you are looking at a modern "portable 88" keyboard from that year, it likely includes: Proteus Release 8.8