This value reports the software revision running on this card in major.minor.maint.patch form, per the description, where each segment has a distinct meaning: major and minor mark the release, maint marks a maintenance build on that release, and patch marks an individual patch on top of the maintenance build. This granular versioning is what an admin uses to confirm whether a specific bug fix (typically shipped as a patch increment) is actually present on this card, rather than just confirming the card is on 'roughly' the right release. Two cards showing the same major.minor but different patch numbers could behave differently for a known, patched issue.