RANCID is software for backing up network device configuration. Mikrotik is a low-power/low-end networking vendor that is supported by RANCID.
RANCID has worked fine prior to v6.49 code, but a code change in Mikrotik v6.49 firmware breaks the RANCID backup. This issue also apparently exists in Mikrotik OS v7.1. The below URLs reference RANCID problems following the upgrade:
https://www.mail-archive.com/rancid-discuss@www.shrubbery.net/msg00170.html
https://forum.mikrotik.com/viewtopic.php?t=179450
The below URL incorporates a (minor) patch to RANCID that fixes the issue (it basically tells the router to use dumb-terminal mode on login). This patch is not incorporated in RANCID at the time of speaking (current latest is v3.13).
https://github.com/haussli/rancid/commit/fef0b6ec166ae2892e8fc6e6a3d0f2de82379c29
I can’t see this being incorporated into a RANCID package for Ubuntu (or one for Debian) before it is fixed upstream (in the RANCID code), so the fix is currently a hack: a manual edit of the respective file.