Numbers '09, 2.3. Please?

My iMac is now running High Sierra and comes with Numbers 4.3.1. The new Numbers has changed a lot, apparently to allow compatibility with iOS apps. Unfortunately for heavy spreadsheet work, it falls WAY short of Numbers 09 versatility. Saved 09 files can be opened in the new operating system, but the top cells are corrupted and it will only print all pages of the whole sheet. My 10 year old iMac still runs but I dislike having to run two iMacs and I'm not sure how long my old one will last. Is there any way to upgrade Numbers 09??? OR, reboot it completely, and replace 4.3.1??? Thanks, Michael