This TS identifies the 3GPP system specifications for Release 15. The specifications and reports of 3GPP Release 15 have a major version number 15 (i.e. 15.x.y). The listed Specifications are required to build a system based on the Evolved Packet System.
The list of Technical Specifications and Technical Reports can be found at:
full Table of Contents for TS 21.201 Word version: 15.0.0