rails version | rspec-rails version
------------- | -------------------
2.3 | 1.3.4
3.0 | >= 2.0
3.1 | >= 2.6
3.2 | >= 2.9
4.0 | >= 2.14
4.1 | >= 3.0
4.2 | >= 3.1
5.0 | >= 3.5
5.1 | >= 3.6
5.2 | >= 3.8
6.0 | >= 4.0