There is a proposal to clarify how to use parallel with declarative, using stages. This has the benefit of allowing config items that naturally live at stage level to be in parallel branches. This may result in some changes in flownodes/bismuth, and how it works with blue ocean visualisations (functionally things are similar):
The declarative ticket for this feature: https://issues.jenkins-ci.org/browse/JENKINS-41334
- See what impact (there may be none) is of running declarative pipelines in this style with bismuth and blue ocean
- potentially make api adjustments/requests.