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Undefined symbols

Unity: All versions | Appodeal SDK: All versions


The error Undefined symbols for architecture arm64: "_OBJC_CLASS_$_SKAdImpression" during the iOS build usually happens if XCode or CocoaPods version is lower than required.
The error log example:

ld: warning: Could not find or use auto-linked framework 'SmaatoSDKUnifiedBidding'
ld: warning: Could not find or use auto-linked framework 'AVFAudio'
ld: warning: Could not find or use auto-linked framework 'AppodealMediationCoreObjC'
Undefined symbols for architecture arm64:
"_OBJC_CLASS_$_SKAdImpression", referenced from:
objc-class-ref in AdColony(ADCAdSession.o)
objc-class-ref in MyTargetSDK(MTRGCommonBannerParser.o)
(maybe you meant: _OBJC_CLASS_$_SKAdImpressionProxy)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

To fix it use the versions listed in the Minimum OS requirements section:

Minimum OS requirements:

  • Unity 2017.4 (Api Compatibility Level - Experimental (.NET 4.6 Equivalent) or 2018.3+

  • Android API level 16 (Android OS 4.1) and above. 

  • iOS 10.0 or higher. 

  • Use XCode 12.5 or higher.

  • CocoaPods 1.10.0 or higher


To update CocoaPods to the latest version, open Terminal and perform the following command:

sudo gem install cocoapods