We have a WebStart application and signed jar files, the old signature certificate
just expired on Sun Nov 12 16:59:59 MST 2017. When launching the WebStart
application, it always pops a security warning

"Unable to ensure the certificate used to identify this application has not been revoked."

Since signature certificate expiration doesn't have any impact on validity of
the jar files signed with it, the WebStart app should work without any
warning.