errors after upgrade to 3.4.6

[Jim Fox]

On a trial uprgade from idp 3.4.4 to 3.4.6 I get this error when invoking 
a duo login.

==================================
2019-11-07 14:48:06,901 - ERROR [org.opensaml.messaging.context.BaseContext:343] - No such method error on creating subcontext
java.lang.NoSuchMethodException: net.shibboleth.idp.authn.context.ExternalAuthenticationContext.<init>()
         at java.lang.Class.getConstructor0(Class.java:3082)
2019-11-07 14:48:06,903 - ERROR [org.springframework.webflow.execution.FlowExecutionException:76] - 
org.springframework.webflow.execution.FlowExecutionException: Exception thrown in state 'DisplayDuoWebView' of flow 'authn/uwduo'
         at org.springframework.webflow.engine.impl.FlowExecutionImpl.wrap(FlowExecutionImpl.java:573)
Caused by: java.lang.IllegalStateException: Exception occurred rendering view org.springframework.web.servlet.view.velocity.VelocityView: name 'duo'; URL [duo.vm]
         at org.springframework.webflow.mvc.view.AbstractMvcView.render(AbstractMvcView.java:208)
Caused by: org.springframework.web.util.NestedServletException: Method invocation failed during rendering of Velocity view with name 'duo': Invocation of method 'getSubcontext' in  class net.shibboleth.idp.authn.context.AuthenticationContext threw exception org.opensaml.messaging.MessageRuntimeException: Error creating subcontext at duo.vm[line 25, column 47]; reference [authenticationContext], method 'getSubcontext'; nested exception is org.opensaml.messaging.MessageRuntimeException: Error creating subcontext
         at org.springframework.web.servlet.view.velocity.VelocityView.mergeTemplate(VelocityView.java:526)
Caused by: org.opensaml.messaging.MessageRuntimeException: Error creating subcontext
         at org.opensaml.messaging.context.BaseContext.createSubcontext(BaseContext.java:344)
Caused by: java.lang.NoSuchMethodException: net.shibboleth.idp.authn.context.ExternalAuthenticationContext.<init>()
         at java.lang.Class.getConstructor0(Class.java:3082)
==================================

This was just a basic "bin/install.sh" upgrade from the 3.4.6 distribution.

Using:

Java(TM) SE Runtime Environment (build 1.8.0_162-b12)
Server version: Apache Tomcat/8.0.28

It's not critical for me, but I'd like some ideas about what's going wrong.

Thanks,
Jim