Besides no version, or a specific one, it is also possible to use logical operators:
'> 0.1' Any version higher than 0.1
'>= 0.1' Version 0.1 and any higher version
'< 0.1' Any version lower than 0.1
'<= 0.1' Version 0.1 and any lower version
In addition to the logic operators CocoaPods has an optimisic operator
'~> 0.1.2' Version 0.1.2 and the versions up to 0.2, not including 0.2 and higher
'~> 0.1' Version 0.1 and the versions up to 1.0, not including 1.1 and higher
'~> 0' Version 0 and higher, this is basically the same as not having it.
For more information, regarding versioning policy, see:
Finally, instead of a version, you can specify the
:head flag. This
will use the pod’s latest version spec version, but force the download
of the ‘bleeding edge’ version. Use this with caution, as the spec
might not be compatible with the source material anymore.