Release notes for 1.15.1

[kjozwiak]

Summary of Changes

This pull request fixes #2467

Submitter Checklist:

• Unit Tests are updated to cover new or changed functionality - N/A
• User-facing strings use NSLocalizableString() - N/A

Test Plan:

N/A

Screenshots:

N/A

Reviewer Checklist:

• Issues include necessary QA labels:
  • QA/(Yes|No)
  • release-notes/(include|exclude)
  • bug / enhancement
• Necessary security reviews have taken place.
• Adequate unit test coverage exists to prevent regressions. N/A
• [ ]~~ Adequate test plan exists for QA to validate (if applicable).~~ N/A
• Issue is assigned to a milestone (should happen at merge time).