arm64 error when updating to Backendless 4
I am updating an existing iOS app to Backendless 4.0. I have fixed all code issues, but am getting the following build error:
Undefined symbols for architecture arm64:
"_OBJC_CLASS_$_UNNotificationAttachment", referenced from:
objc-class-ref in libbackendless.a(MessagingService.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
I am using cocoapods to manage my dependancies. How can I resolve this issue?