Failed resolving Lde/xxx/mobileclient/services/XMPPHelper; interface 3155 ‘Lorg/jivesoftware/smack/MessageListener;’
This messages tells you that dalvik was unable to find the class de.xxx.mobileclient.services.XMPPHelper, which is not part of Smack but extends org.jivesoftware.smack.MessageListener
Hard to say with the provided information, as you didn’t even mention the version of the components involved… The rename is wrong btw, XMPPConnection has become TCPConnection first and is now named XMPPTCPConnection with the latest snapshot of aSmack. Connection has been renamed to XMPPConnection.
If dalvik isn’t able to dynamicall resolve, it’s usually a hint that the build process is fault and that it has used some outdated artifacts. But without knowing your build process, that is all I can say.