Invalid version specification

[ghpb]

Trying to set up the examples I stumple across an invalid version specification

$ yotta ls
error: Invalid version specification: "lancaster-university/mbed-classic#microbit_hfclk+mb6"
error: Invalid version specification: "lancaster-university/BLE_API#v2.5.0+mb3"
error: Invalid version specification: "lancaster-university/nrf51822#v2.5.0+mb7"
error: Invalid version specification: "lancaster-university/nrf51-sdk#v2.2.0+mb4"
error: Invalid version specification: "lancaster-university/mbed-classic#microbit_hfclk+mb6"
error: Invalid version specification: "lancaster-university/BLE_API#v2.5.0+mb3"
error: Invalid version specification: "lancaster-university/nrf51822#v2.5.0+mb7"
error: Invalid version specification: "lancaster-university/nrf51-sdk#v2.2.0+mb4"
microbit-samples 2.0.0-rc8
┗━ microbit 2.0.0-rc8
  ┗━ microbit-dal 2.0.0-rc8 yotta_modules/microbit-dal
    ┣━ mbed-classic lancaster-university/mbed-classic#microbit_hfclk+mb6 missing
    ┣━ ble lancaster-university/BLE_API#v2.5.0+mb3 missing
    ┣━ ble-nrf51822 lancaster-university/nrf51822#v2.5.0+mb7 missing
    ┗━ nrf51-sdk lancaster-university/nrf51-sdk#v2.2.0+mb4 missing

this happens on linux mint 18 (ubuntu) with yotta 0.18.0 setting target to bbc-microbit-classic-gcc. I was following the docs for offline development, Installation on linux. Any help appreciated