CRR, CP/M Read and Reply, was an offline reader for bulletin boards written by Paul Martin. It ran on all CP/M systems but was particularly popular with CPC-owning BBS users.
CRR allowed you to dial up your favourite bulletin board, download all your e-mails and discussion board messages, then disconnect. You could read and reply to them at your leisure, and would only need to reconnect when you wanted to send them. It was compatible with FidoNet bulletin boards which supported certain protocols, such as XRS.
In the author's words from 1991, describing an early version:
CRR is the CP/M offline reader for use anywhere XRS might be used on an MSDOS machine. It allows you to read and reply to downloaded messages from a conforming QBBS, RemoteAccess or SuperBBS Fidonet bulletin board. In order to use this software you will need an archiving program (eg. ARK or ARC), an archive extractor (UNZIP included), and a text editor (eg. VDE or ZDE).