This release contains are-engineered workflow widget, adhering to core api and supporting attached fields.
[#3555256] Fix WorkflowDefaultWidget on basic workflow field
It also contains an open feature request, that already exists since 2015 in several issues for the case that user has on ly 1 transtition option ('single state widget'). Workflow Action buttons (well the last remaining one, in this case) are now ALWAYS visible, and for other widget types you can set the behaviour (hide/show widget or formatter, or hide field completely) , in the configuration for Workflow states,
[#2948377] Fix Do not hide widget when having only one option
Finally some errors fixed:
[#3521903] Fix Fatal error if an exposed views filter has option 'reduce'
[#3554208] Introduce WorkflowUser - add update_hook_8012
[#3559085] by dcoppel: TypeError: WorkflowManager::getOriginal() - revert strict typehinting
[#3560462] Add MarkupInterface for 2 objects
[#3560489] Fix html error in WorkflowStateHistoryFormatter