Update README.md (#26)

* Update README.md

Added note on when to upgrade if errors are coming from the EDOC PROTO

* Update README.md

* Update README.md

Better title for section

README.md

@@ -43,6 +43,11 @@ __Installation is as simple as:__
 pip install thoughtspot-tml
 ```
 
+## Upgrade library after ThoughtSpot is upgraded
+If you have errors using the `.load()` method on a TML file directly exported with no modification from ThoughtSpot, please upgrade to the latest `thoughtpot_tml` version.
+
+New attributes may have been added to the TML specification that are not present in the older version of `thoughtspot_tml` library you have installed.
+
 ## A Basic Example
 
 This example creates a command-line tool for changing the prefix in the names of the Table objects that a Worksheet object connects to.