There is a new configuration entry @CloudVMs.MaxInstances@ (default 64) that limits the number of VMs the cloud dispatcher will run at a time. This may need to be adjusted to suit your anticipated workload.
+Using the obsolete configuration entry @MaxCloudVMs@, which was previously accepted in config files but not obeyed, will now result in a deprecation warning.
+
h3. Slow migration on upgrade
This upgrade includes a database schema update (changing an integer column in each table from 32-bit to 64-bit) that may be slow on a large installation. Expect the arvados-api-server package upgrade to take longer than usual.