# Releases and versions

A firmware release is a number: 103, 105, 106, … Every release is a tag `V<number>` in the
[firmware repository](https://github.com/Source-Robotics/STEPFOC-stepper-controller) and a GitHub release that
carries the image `stepfoc-firmware-V<number>.bin`, a manifest `firmware.json` with the image's size, SHA-256 and
the commit it was built from, and the release notes. The notes are the firmware's changelog; the
[appendix](https://docs.source-robotics.com/STEPFOC-docs/108/appendix/firmware-release-notes/) collects them.

## Which release does my driver run?

```
#Info
```

prints `Software version: <number>` among the rest; Motor GUI shows the same number in the driver's identity, and
over CAN Send_Respond_Device_Info returns it as the third byte. From firmware 105 the number is the build's own
version. Before that it was read from the EEPROM, where the last `#Default` wrote it, so it names the firmware
that last restored the defaults, not necessarily the one running: 101 and 102 write 101, 103 writes 103.

### Drivers that report 103

A driver that reports 103 runs either release 103 from the `main` branch, without a bootloader, or an early build
of the `bootloader-version` branch, which also writes 103 and runs above the bootloader. Some drivers were shipped
with the bootloader before release 105. Which image those carry was not recorded: most likely 103, built for
the bootloader.

To tell whether yours has the bootloader:

- Watch the LED as you switch the driver on: with the bootloader it blinks for about two seconds before the
  firmware starts.
- Or power it up while `bl_flash.py list` or Motor GUI's *Scan bootloaders* is polling: a driver with the
  bootloader answers in its first two seconds.

With the bootloader, update it to the current release as in [Updating through the bootloader](https://docs.source-robotics.com/STEPFOC-docs/108/07-firmware/update/); the
release it ran before does not matter then. Without one, install it first:
[Installing the bootloader on an older board](https://docs.source-robotics.com/STEPFOC-docs/108/07-firmware/bootloader/).

## Which release does this site describe?

The one in the version box on the [landing page](https://docs.source-robotics.com/STEPFOC-docs/108/) and in the version selector in the header. When a
newer release changes what a page says, a new version of the site is published and the previous one stays
reachable from the selector. The [compatibility table](https://docs.source-robotics.com/STEPFOC-docs/108/appendix/compatibility/) says which releases go with
which bootloader, Python library and PAR6 runtime.

## The Spectral Micro counterpart

A change that applies to both drivers comes to the Spectral Micro too, but not always in a release with the same
number: STEPFOC 108 matches Spectral Micro 107. The compatibility table lists the pairs.

## The two branches

Releases from 105 on are built from the `bootloader-version` branch of the repository, whose firmware is linked
to run above the bootloader. The `main` branch holds the firmware of release 103 and earlier, linked to run
without a bootloader, and is not updated. A board running 103 is documented by version `103` of this site; to
move it to a current release, see [Installing the bootloader on an older board](https://docs.source-robotics.com/STEPFOC-docs/108/07-firmware/bootloader/).