Situation: When there are a lot of issues (Maintenance project or Ticketing project) from the field and the current project is team is handling both the things (current project and field issues) which methodology best suits.?

So, in my opinion the answer will be Scrumban (Scrum+Kanban) APPROACH. Because here requirements are changing so frequently which is hampering the current project and sprint.

Scrumban is specially designed for project that requires FREQUENT maintenance, having unexpected user stories and programming errors. Using these approaches, the team’s workflow is guided in a way that ALLOWS minimum completion time for each user story or programming error.

As in this approach we will not take up new task until the high PRIORITY task has reached the deploy state.

Few tips for selecting the PROCESS are:

1. Integrate workflows with a task list for better transparency. -Kanban
2. Scrum for continuously devotion to projects
3. Visualization of workflow-Kanban
4. Intense human collaboration and feedback-Scrum.