While many are currently on version 2022 LTS, there is often confusion regarding version numbers.
To run Unity Pro 13.1 effectively, your system should meet the following minimum and recommended specifications: Unity Pro 13.1_EN - Complete Documentation Unity Pro 13.1 Download
If you cannot obtain a legal copy of v13.1, consider these options. While many are currently on version 2022 LTS,
To ensure a smooth Unity Pro 13.1 download and installation, your workstation should meet or exceed these specifications. Unity Pro 13.1 Download