/etc/update-manager/release-upgrades.d configs ignored

[Jose L. VG]

In my tests the /etc/update-manager/release-upgrades.d directory does not seem to be taken into account for overriding the configuration at:
/etc/update-manager/release-upgrades

Testing on trusty, I have tried this file:
[DEFAULT]
# Override prompting behavior to 'never' check for new release
Prompt=never

With these names:
/etc/update-manager/release-upgrades.d/release-upgrades
&
/etc/update-manager/release-upgrades.d/99never-upgrade

And:
rm /var/lib/ubuntu-release-upgrader/release-upgrade-available
root@trelease:~# /usr/lib/ubuntu-release-upgrader/release-upgrade-motd
Will always reproduce the output:
New release '16.04.1 LTS' available.
Run 'do-release-upgrade' to upgrade to it.

While changing /etc/update-manager/release-upgrades does work as expected

[Brian Murray (brian-murray)]

Well, the changelog leads one to believe it should work although I haven't found any code that actually checks that directory.

update-manager (1:0.99) jaunty; urgency=low

  [ Michael Vogt ]
  * DistUpgrade/DistUpgradeController.py:
    - enable apport crash capturing during upgrades
  * DistUpgrade/DistUpgradeView.py:
    - create /var/lib/pycentral/pkgremove before the upgrade to
      help pycentral transition to the new python policy (thanks
      to doko)
  * ensure pidgin-libnotify is upgraded (LP: #332328)
  * better wording for aborts (thanks to Gabor Kelemen and
    Jean-Baptiste Lallement), LP: #289303
  * wording fixes, thanks to Brian Murray and Gabor Kelemen
    LP: #269583
  * i18n fix, thanks to Gabor Kelemen, LP: #331821
  * support /etc/update-manager/release-upgrades.d/ directory
    for local overrides of the upgrade process. Useful to force
    certain site-specific options (like third party repository
    handling)

[Björn (bjmi)]

This issue still exists in Ubuntu Bionic.

After several tries to override
/etc/update-manager/release-upgrades
with a file placed in
/etc/update-manager/release-upgrades.d/
this issue come to my resuce let me stop searching for an error on my side.

Maybe this issue could be planned for the next release.