Retry flag not working?

[odlp]

When I run the following command:

bundle exec appraisal install --retry 3

I get an error:

ERROR: "appraisal install" was called with arguments ["--retry", "3"]
Usage: "appraisal install"

But the source suggests this flag should be accepted: https://github.com/thoughtbot/appraisal/blob/5675d17a95cfe904cc4b19dfd3f1f4c6d54d3502/lib/appraisal/cli.rb#L44

---

Ruby version (via Rbenv): ruby 2.3.3p222 (2016-11-21 revision 56859) [x86_64-darwin15]

Gems:

Using rake 12.0.0
Using public_suffix 2.0.5
Using bundler 1.14.6
Using thor 0.19.4
Using diff-lcs 1.3
Using mini_portile2 2.1.0
Using rspec-support 3.5.0
Using addressable 2.5.0
Using appraisal 2.1.0
Using nokogiri 1.7.0.1
Using rspec-core 3.5.4
Using rspec-expectations 3.5.0
Using rspec-mocks 3.5.0
Using postrank-uri 1.0.20 from source at `.`
Using rspec 3.5.0

[odlp]

Solved my own issue... I'm using Appraisal 2.1.0 (latest release on rubygems - from August 2015) but the retry feature was added March 2016