The patent may be expired, but an enhancement to it might be granted a new patent, and your implementation might inadvertently infringe on the enhancement. Ther

The patent may be expired, but an enhancement to it might be granted a new patent, and your implementation might inadvertently infringe on the enhancement. There may also be cases where two patents cover the same algorithm. Be careful about assuming a patent has expired, terms have changed in the past and you have to consider foreign patents as well.