Indiana Code Title 6. Taxation § 6-2.5-1-24

(1) The combining of two (2) or more prewritten computer software programs or prewritten parts of the programs does not cause the combination to be other than prewritten computer software.

(2) Prewritten computer software includes software designed and developed by the author or other creator to the specifications of a specific purchaser when it is sold to a person other than the purchaser.

(3) If a person modifies or enhances computer software of which the person is not the author or creator, the person is considered to be the author or creator only of the person's modifications or enhancements.

(4) Prewritten computer software or a prewritten part of the software that is modified or enhanced to any degree, where the modification or enhancement is designed and developed to the specifications of a specific purchaser, remains prewritten computer software.  However, where there is a reasonable, separately stated charge or an invoice or other statement of the price given to the purchaser for such a modification or enhancement, the modification or enhancement is not prewritten computer software.