Is it necessary to buy new Open Type fonts to replace Truetype fonts? We have almost 2,000 fonts we are currently using at my job. Many are Truetype and seem to work just fine even though they are 20 years old. We do primarily packaging artworks for print, we do not do any web work. Is Open Type necessary? Thanks!

Not sure to understand.
If it's working with TTF, why would you change them to OTF?
Did you face any problem with your TTF?