Upgrading from 2.370 (a weekly release from over a year ago) needs a review of multiple LTS changelogs and multiple upgrade guides. Review and heed the concerns in all of them.
Persuade your organization that they should allocate time to upgrade monthly rather than delaying upgrades. When you delay upgrades, you accumulate a larger set of changes that need to be evaluated and considered during an upgrade.
The Jenkins project provides security support for the most recent LTS release and the most recent weekly release. You should choose the most recent LTS release and should plan to upgrade it monthly.
Video tutorial available at
I’m not aware of anyone that offers project based support for Jenkins. I’m confident that there are many DevOps consultants that you could hire as consultants, but I’m not aware of any specific examples.