There are three changes, the first two are breaking.

The two breaking changes are in three command-monitoring tests: "bulkWrite.yml", "unacknowledgedBulkWrite.yml" and "insertMany.yml":

https://github.com/mongodb/specifications/commit/bebf9b688f64afdec46a860f102bad0841b04c02

The format of the "requests" array and "ordered" option changes from this:

    operation:
      name: "bulkWrite"
      arguments:
        requests:
          - insertOne: 
              document: { _id: 4, x: 44 }
        ordered: false

To this:

    operation:
      name: "bulkWrite"
      arguments:
        requests:
          - name: "insertOne"
            arguments:
              document: { _id: 4, x: 44 }
        options:
          ordered: false

This brings Command Monitoring tests in line with the Retryable Writes and forthcoming Transactions tests.

The non-breaking change is in the Retryable Writes tests:

https://github.com/mongodb/specifications/commit/c0ce96daac5661f2603bfa52c9b3f683c176a292

Before, the tests said in prose that all MongoClients should be created with retryWrites=true. Now, the tests include the following YAML:

        clientOptions:
            retryWrites: true

The clientOptions are the same for all Retryable Writes tests. Interpreting this field now will prepare you for the Transactions tests, which make real use of the field.