Testrail:

• Close previous test plans from below latest "auto-generated" one AND remove 'auto-generated' in front of current run name before closing.
  -milestones --> add milestone --> Name '4.5.2' etc
  -milestones --> old milestone --> check 'This milestone is completed' --> save
• test runs & results --> latest run --> edit --> map milestone to run --> save

Close the test run when results are in, comments done if needed and results are reviewed for release! This ensures test resuls for each and every one of releases is 'frozen'.
Developing new tests and running them in RTA will otherwise mess up the release test results by pushing new results from new tests over the release test results!

• Choose test plan, choose edit from right top corner --> Close this test plan