Swift version error on Objective-C base project

[gurhub]

Hi,

I try to install the library via Cocoapods (in a freshly created Objective-C demo project) and I got the error below:

[!] Unable to determine Swift version for the following pods:

• DATAStack does not specify a Swift version and none of the targets (DNP) integrating it have the SWIFT_VERSION attribute set. Please contact the author or set the SWIFT_VERSION attribute in at least one of the targets that integrate this pod.

Unfortunately couldn't install the library.

my Podfile line is below:

pod 'DATAStack', '~> 6'

Best