1) Becoming obsolete 2) Noncurrent 1) Dying 2) Noncurrent 3) Out 
reduced to the point of being vestigal
• (a.) Going out of use; becoming obsolete; passing into desuetude.
Ob`so·les'cent adjective [ Latin obsolescens , -entis , present participle of obsolescere , to wear out gradually, to fall into disuse; ob (see Ob- ) + solere to use, be wont.] Going out of use; becoming obsolete; passing into desuetude. 
Nearly obsolete; becoming rudimentary.
reduced to the point of being vestigal
[adj] - becoming obsolete
obsolescent 1. Becoming obsolete; passing out of use, as a word: 'He was using an obsolescent term.' 2. Becoming outdated or outmoded, as machinery or weapons. 3. In biology, gradually disappearing; imperfectly or only slightly developed. A reference to an organ or other part of an animal or plant.
adjective becoming obsolete