Add clarification around reverting changes that touch DynamoDB data (#…

…982)

A revert is essentially a delete, but I don't think many of us would
treat one the same as an explicit delete given that generally reverting
code is a safe operation :)

tron/config/config_parse.py

@@ -3,7 +3,8 @@
 contain a validated configuration.
 
 
-WARNING: it is *NOT* safe to delete classes that are being validated (or their attributes) if there are any references to them in DynamoDB! (See DAR-2328)
+WARNING: it is *NOT* safe to delete classes that are being validated (or their attributes) if there are any references to them in DynamoDB until TRON-2200 is complete! (See DAR-2328)
+NOTE: this means that reverting a change that adds a new attribute is not safe :)
 """
 import datetime
 import getpass

tron/config/schema.py

@@ -1,6 +1,7 @@
 """
  Immutable config schema objects.
- WARNING: it is *NOT* safe to delete these classes (or their attributes) if there are any references to them in DynamoDB! (See DAR-2328)
+ WARNING: it is *NOT* safe to delete these classes (or their attributes) if there are any references to them in DynamoDB until TRON-2200 is complete! (See DAR-2328)
+ NOTE: this means that reverting a change that adds a new attribute is not safe :)
 """
 from collections import namedtuple
 from enum import Enum
@@ -325,4 +326,5 @@ def _asdict(self) -> dict:
 
 ActionOnRerun = Enum("ActionOnRerun", dict(rerun="rerun"))  # type: ignore
 
-# WARNING: it is *NOT* safe to delete these classes (or their attributes) if there are any references to them in DynamoDB! (See DAR-2328)
+# WARNING: it is *NOT* safe to delete these classes (or their attributes) if there are any references to them in DynamoDB until TRON-2200 is complete! (See DAR-2328)
+# NOTE: this means that reverting a change that adds a new attribute is not safe :)