Actually, Melbro - it loaded wdm for JRiver Media Center 25.
I had actually uninstalled MC 25, and supposedly also the JRMC25 WDM driver, however the WDM apparently is still that for JRMC25, as shown in Device manager - control panel in Audio Inputs and Outputs.
Had unchecked WDM in Option->General->Features & restarted JRMC26, then checked WDM and restarted, but the WDM still appeared as JRMC25's driver.
Checked Properties for the WDM that appears as an input in Device manager, then went to Events tab on Properties screen.
There were 3 events generated resulting from re-starting JRMC26 with WDM checked:
#1 - Device startede
#2 - Device configured (audioendpoint.inf)
#3 - Device not migrated.
Information for 3rd event showed an error code with text "was not migrated due to partial or ambiguous match".