While the exact software version isn't explicitly stated in the problem details, the logs and the mentioned bug CSCvv91944 point towards a version in the 16.12.x family, with 16.12.3a being a plausible candidate based on the provided list. The problem describes an issue with Power over Ethernet (PoE) detection and errors, which is a known bug addressed in newer software versions. Since the customer is using an older code, upgrading is recommended for a permanent fix. The software version 16.12.3a is selected from the given list as it aligns with the context of the known bug and the suggestion to upgrade.
The software version is not explicitly provided but inferred as 16.12.3a due to the known bug and recommendations.