I replaced:
| Package: plymouth | ... | Replaces: plymouth-drm (<< 0.9.0-6~), plymouth-themes (<< 0.9.0-8~)
With:
| Package: plymouth | ... | Replaces: plymouth-drm (<< 0.9.0-6~), plymouth-themes (<< 0.9.0-8~), libplymouth2
And that seems to fix things for me. Note that this is upgrading a Trusty instance in Canonistack to Xenial.
I replaced:
| Package: plymouth
| ...
| Replaces: plymouth-drm (<< 0.9.0-6~), plymouth-themes (<< 0.9.0-8~)
With:
| Package: plymouth
| ...
| Replaces: plymouth-drm (<< 0.9.0-6~), plymouth-themes (<< 0.9.0-8~), libplymouth2
And that seems to fix things for me. Note that this is upgrading a Trusty instance in Canonistack to Xenial.