Detect your current Raspberry Pi version.
Example (try it right now!):
>>> curl -s https://raw.githubusercontent.com/tompreston/raspi-version/master/raspi_version.py | python3
Revision: a01041
Release date: Q1 2015
Model: 2 Model B
PCB Revision: 1.1
Memory: 1 GB
Notes: Mfg by Sony
Board revisions are here. Keep up to date if you see any inconsistencies.