I am trying to upgrade JIRA from 5.2.11 to 6.3.12 but i am having issues:
Exception thrown during upgrade: com.atlassian.util.concurrent.LazyReference$InitializationException: com.atlassian.util.concurrent.LazyReference$InitializationException: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.keplerrominfo.jira.plugins.usergrouppicker.UserCFType': Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.keplerrominfo.jira.plugins.usergrouppicker.UserCFType]: Constructor threw exception; nested exception is java.lang.NoSuchMethodError: com.atlassian.jira.issue.customfields.impl.UserCFType.(Lcom/atlassian/jira/issue/customfields/persistence/CustomFieldValuePersister;Lcom/atlassian/jira/issue/customfields/converters/UserConverter;Lcom/atlassian/jira/issue/customfields/manager/GenericConfigManager;Lcom/atlassian/jira/config/properties/ApplicationProperties;Lcom/atlassian/jira/security/JiraAuthenticationContext;Lcom/atlassian/jira/bc/user/search/UserPickerSearchService;Lcom/atlassian/jira/issue/fields/rest/json/beans/JiraBaseUrls;Lcom/atlassian/jira/user/UserHistoryManager;)V com.atlassian.cache.CacheException: com.atlassian.util.concurrent.LazyReference$InitializationException: com.atlassian.util.concurrent.LazyReference$InitializationException: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.keplerrominfo.jira.plugins.usergrouppicker.UserCFType': Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.keplerrominfo.jira.plugins.usergrouppicker.UserCFType]: Constructor threw exception; nested exception is java.lang.NoSuchMethodError: com.atlassian.jira.issue.customfields.impl.UserCFType.