Could not find remote branch 2.2 to clone

[dkhode]

pod install:
Error:
[!] Error installing FHIR
[!] /usr/bin/git clone https://github.com/smart-on-fhir/Swift-FHIR.git /var/folders/mq/b_s7ht696vd3xkr6m5qz13ww00134y/T/d20161121-51618-1ey3k3n --single-branch --depth 1 --branch 2.2

warning: Could not find remote branch 2.2 to clone.
fatal: Remote branch 2.2 not found in upstream origin

My Podfile looks like:

pod 'AFNetworking', '> 2.2'
pod 'AFNetworking-RACExtensions', '> 0.1'
pod 'BlocksKit', '> 2.2'
pod 'Classy'
pod 'CRToast', '> 0.0'
pod 'iCarousel', '> 1.8.1'
pod 'JSONModel'
pod 'MMPReactiveStompClient', '> 0.2'
pod 'PDKeychainBindingsController', '> 0.0'
pod 'SocketRocket', '> 0.4'

use_frameworks!
pod 'FHIR', '2.2'
pod 'Alamofire', '> 3.0'
pod 'Charts', '> 2.2'
pod 'JWTDecode', '> 1.0'
pod 'ObjectMapper', '1.1.5'
pod 'Starscream', '> 1.1'

target :CertifyHLTests do
pod 'BlocksKit', '~> 2.2'
end

[p2]

Any particular reason you're using 2.2 and not ~> 2.2, which would use 2.2.4?