Arm Mbed OS support forum

Cloud OS6.3 reports version 5.14.2?

After looking at the Mbed OS 6.3 release notes, I used the cloud environment to test this.

Step 1) New Program “mbed OS Blinky LED HelloWorld”.

1a) click on “mbed-os” and look at the Revision (it showed the 2nd newest - revision aa70f680bb). I updated to the newest 0db72d0cf2, which has in the comment "tag::mbed-os-6.3.0.

Step 2) I added 3 lines of code, creating a main.cpp like you see here:

/* mbed Microcontroller Library
 * Copyright (c) 2019 ARM Limited
 * SPDX-License-Identifier: Apache-2.0

#include "mbed.h"
#include "platform/mbed_thread.h"

Serial pc(USBTX, USBRX, 460800);    // ADDED

// Blinking rate in milliseconds
#define BLINKING_RATE_MS                                                    500

int main()
    printf("mbed booted! Target %s, Build %s %s\r\n", MBED_STRINGIFY(TARGET_NAME), __DATE__, __TIME__);   // ADDED
    printf("             v %d.%d.%d\r\n", MBED_MAJOR_VERSION, MBED_MINOR_VERSION, MBED_PATCH_VERSION);   // ADDED
    // Initialise the digital pin LED1 as an output
    DigitalOut led(LED1);

    while (true) {
        led = !led;

Step 3) Build, download, program and reset the target

Step 4) Target emits the following:
mbed booted! Target LPC1768, Build Sep 28 2020 14:00:15
v 5.14.2

Should I have seen 6.3.0 instead of 5.14.2?


I’m sure you not use MbedOS6+ because compiler let you compile Serial Api.
But you are right same on NucleoF429ZI.

BR, Jan

Thank you for the quick follow-up. I made mention of the revision that had 6.3.0 in the comment - here’s the graphic. Although the highlight is on it, you can see that the revision is bold, indicating it is the active revision.

Even though it has the green circle on mbed-os, the lower revision pane is empty, and the upper is as you see above.

And it accepted the Serial object - which you suggested it should not.

I would like to think this is easily reproducible by creating a new project - unless it is somehow LPC1768 specific. I also removed all .bin files from my target, rebooted it to ensure it was then “dead”, then put the just built bin on it.

Yes, you are right David. I badly check the numbers in your original post, sorry.
In the MbedStudio IDE it seems be OK.

I sent a mail to the Mbed support about it, so we will see.

BR, Jan

Thanks for getting in touch with the Mbed team. This email address is no longer monitored but you can get help with Mbed OS, the online compiler and Mbed Studio on our community forums (

Ok, then @JoeA @AnnaBridge

Hi @WiredHome,

We have resolved the issue with Mbed OS 6.3 incorrectly using 5.14 inside the Online Compiler. The issue was caused by part of our release process for new versions silently failing and thus releasing the wrong version. Mbed OS 6.3 and 6.4 are now correctly available, and we have added an additional check to our release process to prevent this issue in the future.