My solution, a snippet of code, is below
cursorUpd = db.cursor()
#set version
cursorUpd.callproc('sde.version_util.set_current_version',['MyVersion'])
#start editing
cursorUpd.callproc('sde.version_user_ddl.edit_version',['MyVersion',1])
#SQL for update
cursorUpd.execute("UPDATE xxx set REVIEWNOTES = 'TEST " + currDay + "' WHERE ORIGGUID = " + matchGUID)
#stop editing, save
cursorUpd.callproc('sde.version_user_ddl.edit_version',['MyVersion',2])
db.commit()
Hopefully this is helpful. I initially tried to do this through a single large execute block, with all the calls inside the execute block, but the bind variables for the update statement would not work, no matter how they were formatted. The above works for me.