On the contractor details screen, there is now the ability to changed the status of a contractor to closed. This is useful if you have some contractors who you don't want to use again. They cannot be deleted, because they have history associated with them, but they can be closed.
There is also the ability to hide or show closed contractors on the contractors list screen, just like you can do with tenants and owners.
When creating a new work order or quote, only open contractors will be visible. However if you open an existing job associated with one of the closed contractors, you will still be able to select that contractor.