The analogue phone network PSTN (public switched telephone network) will be switched off in 2027 and all phone lines will become digital.
Digital lines (SoGEA) and fibre broadband (FTTC and FTTP) will replace the old analogue services.
VoIP phone systems provide a replacement for analogue PBX systems.
Any analogue systems that rely on PSTN such as fax machines will stop working at this point. These can be integrated into your VoIP system by using analogue telephone adapters (ATAs).
PSTN switch off 2027 Digital lines, broadband and VoIP phone systems will replace the PSTN voice network.
Please see here for more information:
Digital lines
VoIP phone systems
Fax and ATAs