Undefined symbols "_OBJC_CLASS_$_SKAdImpression"

XCode: 12.4 or lower | Appodeal SDK: 2.10.1+

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 update XCode to 12.5 or higher and CocoaPods to 1.10.0 or higher.

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

sudo gem install cocoapods