Hi Mike,
The confusion may be a result of the time difference. By the time you were asking for the libraries, I had made several attempts to remedy the issue, one of which was successful.
The dot library being used for my programs is libmDot-dev-mbed5, as found at https://developer.mbed.org/teams/MultiTech/code/libmDot-dev-mbed5/.
Currently I have programs using both mbed.bld (top search result under import programs search) and mbed-dev.
The version of mbed-rtos I am using, according to the mbed compiler, is https://developer.mbed.org/users/mbed_official/code/mbed-rtos/
Thank you for the note about mbed-os, I had not previously seen it used by other programs and so wasn’t aware of it.
Kind regards