A method performed by an IP Multimedia Subsystem, IMS, (102, 400), the method comprising: receiving a first Session Initiation Protocol, SIP, INVITE message to initiate a first voice communication session with a first wireless communication device; obtaining first device capability information from the first SIP INVITE message, wherein the first device capability information indicates whether the first wireless communication device supports 5th-Generation, 5G, cellular communications, wherein the first device capability information is within an Information Element, IE, of the first SIP INVITE message, wherein the IE is in the form of a binary flag indicating whether or not the device supports 5G cellular communications; determining that the first device capability information indicates that the first wireless communication device supports 5G cellular communications, wherein the determining is based on the IMS determining that the IE contains the binary flag indicating that the device supports 5G cellular communications; in response to determining that the first device capability information indicates that the first wireless communication device supports 5G cellular communications, communicating with a 5G Policy Control Function, PCF, to establish a first dedicated bearer with the first wireless communication device; receiving a second SIP INVITE message to initiate a second voice communication session with a second wireless communication device; obtaining a second device capability information from the second SIP INVITE message, wherein the second device capability information indicates whether the second wireless communication device supports 5th-Generation, 5G, cellular communications; wherein the second device capability information is within an Information Element, IE, of the second SIP INVITE message, wherein the IE is in the form of a binary flag indicating whether or not the device supports 5G cellular communications; determining that the second SIP INVITE message does not indicate that the second wireless communication device supports 5G cellular communications, wherein the determining is based on the IMS determining that the IE contains the binary flag indicating that the device does not support 5G cellular communications; and in response to determining that the second SIP INVITE message does not indicate that the second wireless communication device supports 5G cellular communications, communicating with a 4G Policy and Charging Rules Function, PCRF, to establish a second dedicated bearer with the second wireless communication device. receiving a first Session Initiation Protocol, SIP, INVITE message to initiate a first voice communication session with a first wireless communication device; obtaining first device capability information from the first SIP INVITE message, wherein the first device capability information indicates whether the first wireless communication device supports 5th-Generation, 5G, cellular communications, wherein the first device capability information is within an Information Element, IE, of the first SIP INVITE message, wherein the IE is in the form of a binary flag indicating whether or not the device supports 5G cellular communications; determining that the first device capability information indicates that the first wireless communication device supports 5G cellular communications, wherein the determining is based on the IMS determining that the IE contains the binary flag indicating that the device supports 5G cellular communications; in response to determining that the first device capability information indicates that the first wireless communication device supports 5G cellular communications, communicating with a 5G Policy Control Function, PCF, to establish a first dedicated bearer with the first wireless communication device; receiving a second SIP INVITE message to initiate a second voice communication session with a second wireless communication device; obtaining a second device capability information from the second SIP INVITE message, wherein the second device capability information indicates whether the second wireless communication device supports 5th-Generation, 5G, cellular communications; wherein the second device capability information is within an Information Element, IE, of the second SIP INVITE message, wherein the IE is in the form of a binary flag indicating whether or not the device supports 5G cellular communications; determining that the second SIP INVITE message does not indicate that the second wireless communication device supports 5G cellular communications, wherein the determining is based on the IMS determining that the IE contains the binary flag indicating that the device does not support 5G cellular communications; and in response to determining that the second SIP INVITE message does not indicate that the second wireless communication device supports 5G cellular communications, communicating with a 4G Policy and Charging Rules Function, PCRF, to establish a second dedicated bearer with the second wireless communication device.