Releasing Serial Modem

Before each official release or pre-release, update the following version metadata. Each published application image must carry a higher MCUboot sign version than the previous one on the same product line. Increment CONFIG_FW_INFO_FIRMWARE_VERSION only when the MCUboot bootloader image changes.

Application - app/VERSION

app/VERSION is the single source of truth for:

  • The major.minor.patchlevel prefix in AT#XSMVER <sm_version> (Git-describe style: v + that triplet + optional -N-g<hash> from Git).

  • The MCUboot application sign version (CONFIG_MCUBOOT_IMGTOOL_SIGN_VERSION, major.minor.patchlevel+VERSION_TWEAK), used for application downgrade prevention during DFU.

See Zephyr application VERSION.

DFU and AT#XSMVER

For application firmware update, a host can read AT#XSMVER before and after DFU and compare the major.minor.patchlevel prefix of <sm_version> (the part from app/VERSION, before any -N-g<hash> Git suffix). That value must increase when moving to a newer published image. MCUboot enforces the same ordering using the sign version derived from app/VERSION. The Git suffix is informational only and is not used for downgrade checks.

Pre-release numbering

Before General Availability (GA) for a target X.Y.Z, use a staging line below X.Y.Z and increment PATCHLEVEL for each published pre-release. Keep VERSION_TWEAK = 0 unless you have a specific reason to use it after GA.

v2.0.0 GA

The first v2.0.0 pre-release uses 1.99.0, the second 1.99.1, and so on. At GA, set the product version to 2.0.0.

# First v2.0.0 pre-release
VERSION_MAJOR = 1
VERSION_MINOR = 99
PATCHLEVEL = 0
VERSION_TWEAK = 0

# Second v2.0.0 pre-release
VERSION_MAJOR = 1
VERSION_MINOR = 99
PATCHLEVEL = 1
VERSION_TWEAK = 0

# v2.0.0 release
VERSION_MAJOR = 2
VERSION_MINOR = 0
PATCHLEVEL = 0
VERSION_TWEAK = 0

2.0.0+0 must be greater than every shipped 1.99.N+0 pre-release.

Future v2.1.0 GA

Pre-releases before v2.1.0 GA, use the 2.0.99 line (for example 2.0.99, then 2.0.100), incrementing PATCHLEVEL for each published pre-release, following the same pattern as 1.99.0, 1.99.1 before v2.0.0 GA. At v2.1.0 GA, set VERSION_MAJOR, VERSION_MINOR, and PATCHLEVEL to 2, 1, and 0.

General Availability and later

The following guidelines describe how to manage versioning for General Availability and later:

  • Set the product version and VERSION_TWEAK = 0 at GA.

  • After GA, increment PATCHLEVEL for each new published application build on that line.

  • Do not update version fields for unpublished local or CI builds.

  • Record the mapping between Git tag and app/VERSION in the release notes,

  • Confirm the version with AT#XSMVER.

MCUboot — CONFIG_FW_INFO_FIRMWARE_VERSION

In app/sysbuild/mcuboot/prj.conf, increment the value only when the MCUboot bootloader image changes. The value is used by NSIB (B0) for MCUboot slot downgrade prevention and is independent of app/VERSION.

After an MCUboot update, AT#XBOOTINFO=0 reports the active slot value.

See Release notes for more information.