Hello,
You can ignore this, it doesn’t have anything together with MbedOS version. However the installation contains also approx one year licence (date limited not from installation) for Arm Compiler 6 which is not free in normal way. And that lead us to the root cause because latest version seems to be 1.4.6 - Installing Mbed Studio - Installing | Mbed Studio Documentation.
BTW do not miss - Important update on Mbed - End of Life - Mbed OS - Arm Mbed OS support forum
BR, Jan