After upgrade, methods referencing GsHostProcess require recompilation
The upgrade to 3.6.4 involves changes to the GsHostProcess class; the old GsHostProcess class is renamed ObsoleteGsHostProcess, and any references to this class, such as in compiled methods, will refer to the older class.
The methods in ObsoleteGsHostProcess depended on primitives that have had incompatible modifications, so the upgrade process removes all methods from ObsoleteGsHostProcess. Any messages sent to a referenced class, such as code executing in these compiled methods, will error with a messageNotUnderstood.
After upgrade, any methods with embedded references to GsHostProcess should be recompiled, so they will refer to the new class. This was inadvertently not mentioned in the Release Notes for v3.6.4.
Last updated: 7/28/22