Cannot edit SDE data with Python update or insert cursors

Description

Update and insert cursors fail when trying to edit SDE data using a Python script. For example, the script below should edit field values in an SDE feature class. This code runs without error, however, the attribute values are not changed.

Code:
from win32com.client import Dispatch
gp=Dispatch("esriGeoprocessing.GPDispatch.1")
gp.workspace="Database Connections/Ora9204Helium.sde"
try:
    table = "SYSTEM.rn_test"
    rows = gp.UpdateCursor(table,  "SHAPE.LEN > 20")
    row = rows.next()
    while row:
        row.ATTR = 200
        rows.UpdateRow(row)
        row = rows.next()
except:
    del rows
    del row

Cause

This is a known limit. This is only a problem with versioned SDE data. If the data is not versioned, then the above code works as expected.

Workaround

Note:
More information can be found on Disconnected Editing in the ArcGIS Desktop Help. Select Building a Geodatabase > Disconnected editing on the Contents tab.