Support for INOUT parameters in MySQL

I’m using DF 2.3.0 on a Bitnami AWS EC2 instance, with a MySQL service to an AWS RDS instance. I have a bare bones stored procedure with a single INOUT parameter of type JSON.

(INOUT Input_Output_JSON_SP_Pararm TEXT)

In my POSTMAN testing POST script, I have the following request:
“name”: “Input_Output_JSON”,
“param_type”: “INOUT”,
“type”: “text”,
“value”: “[{“dummy”:“any string”}]”

When I leave param_type as “IN” (both in the MySQL sproc, and in the POSTMAN request), everything executes correctly without error. I believe DF supports a MySQL sproc “INOUT” parameter. However, when I change the same MySQL parameter type to “INOUT”, I receive an error similar to the following:

“Failed to call database stored procedure.\nSQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘[{“dummy”:“any string”}]’ at line 1 (SQL: SET @Input_Output_JSON_SP_Pararm = [{“dummy”:“any string”}]; )”

The change I make is strictly to the MySQL stored proc (changing “IN” to “INOUT”). The POSTMAN request params do not change, yet the error message says that the stored proc is not accessed. The error feels like a parsing issue, but I’m just guessing.
Any suggestions would be much appreciated.