We have migrated a Production instance from JIRA 6 to JIRA 7.5 and some external scripts stopped working.
You could indicate the corrections to be made in:
import com.atlassian.jira.ComponentManager
import com.atlassian.jira.issue.CustomFieldManager
import com.atlassian.jira.issue.Issue
import com.atlassian.jira.issue.MutableIssue
import com.atlassian.jira.issue.comments.CommentManager
import com.atlassian.jira.issue.fields.CustomField
import com.atlassian.jira.util.ImportUtils
import com.atlassian.jira.user.util.DefaultUserManager
import com.atlassian.crowd.embedded.api.User
import com.atlassian.jira.project.Project
import com.atlassian.jira.component.ComponentAccessor
MutableIssue issue = issue
Project project = issue.getProjectObject()
def componentManager = ComponentManager.getInstance()
def customFieldManager = ComponentAccessor.getCustomFieldManager()
def component = componentManager.getProjectComponentManager().findByComponentName(project.getId(),'Instalaciones')
issue.setComponents([component.getGenericValue()])
Thank you very much.