Eclipse Californium (Cf) CoAP Framework 2.3.1

Bugfix Release:

Changes:

• 74f923c3a 2020-09-01 Update benchmark to 2.3.1-SNAPSHOT.
• 48b8e1d2a 2020-09-01 Disable netstat logger for windows.
• f8c85eb9b 2020-09-01 Fix cookie generator.
• 61695f7a8 2020-08-10 Report unresolved address with IllegalArgumentException as send error.
• 16be4dc03 2020-08-12 Provide better error messages for certificate checks.
• c1787726e 2020-07-25 Fix java 7 NullPointerException in MessageDigest.isEqual.
• 002a840cf 2020-07-06 Slightly relax rules for server only and handshake modes