The question posted is not that clear.
If you are talking about the helper class which is part of the custom bundle deployed in OSGI , then either bundle is not active or the component is not active . That might be because of one(or few) of the dependencies are not resolved new to bundle versions.
Once the pom.xml is updated with the right version for the bundles which are not supported with the newer version of AEM , this issue should be resolved.