I noticed recently on my N900 and N9 that attempting to run nano over ssh resulted in the following error:
and mc started in black & white.

I found that in Ubuntu 15.10 the TERM environment variable now defaults to xterm-256color instead of xterm-color.
Apparently this changed in a recent upgrade to Apple OS X as well.
This environment variable is passed through when ssh-ing into another machine.

Both Maemo and Harmattan have an old version of ncurses-base (5.7+20081213) which includes the file /etc/terminfo/x/xterm-color but not /etc/terminfo/x/xterm-256color.

One solution is to set the TERM environment variable after ssh-ing into the device:
Another solution is to copy the file /lib/terminfo/x/xterm-256color from a recent Debian or Ubuntu installation (or the attached xterm-256color.tar.gz from the Maemo package) to /etc/terminfo/x/ on the device.