---
upgrade:
  - |
    Upgrading to Train on a deployment with a large database may hit
    `bug 1862205`_, which results in instance records left in a bad
    state, and manifests as instances not being shown in list
    operations. Users upgrading to Train for the first time will
    definitely want to apply a version which includes this fix.  Users
    already on Train should upgrade to a version including this fix to
    ensure the problem is addressed.

    .. _bug 1862205: https://launchpad.net/bugs/1862205
fixes:
  - |
    A fix for serious `bug 1862205`_ is provided which addresses both
    the performance aspect of schema migration 399, as well as the
    potential fallout for cases where this migration silently fails
    and leaves large numbers of instances hidden from view from the
    API.