A base station apparatus for communicating with a terminal apparatus transmits a Radio Resource Control (RRC) connection reconfiguration request message including a Data Radio Bearer (DRB) configuration to the terminal apparatus. The DRB configuration includes a DRB identity and a Packet Data Convergence Protocol Layer (PDCP) entity configuration corresponding to the DRB identity. PDCP entity configuration information includes one of a PDCP entity configuration for Evolved Universal Terrestrial Radio Access (E-UTRA) and a PDCP entity configuration for New Radio (NR). A PDCP entity is established in accordance with the PDCP entity configuration information.